F
FOOL - FOOLISHNESS

FOOL - adjectives (also see FOOLISH)
• BILLY-WHIFFLING playing the fool ...Bk1898 Eng. dial.
fool - nouns 
• BOOBOLOGY the study of fools ...Bk1942 Amer. sl.
• DORK-FACTOR the number of fools ...1970s US campus sl.
• FEATHER IN THE CAP, A † the badge of a fool ...a1700
• FOOLOLOGY. the study of fools ...Bk1942 Amer. sl.
• JACKASSIFICATION n. the act of making a jackass or fool of ...1822 nonce word
• MOROLOGY the science that treats of fools ...1867 humorous
• NUTOLOGY the study of fools ...Bk1942 Amer. sl.
fool - person (includes foolish person)
• AARDVARK a slow-witted person having a coarse or foolish appearance; an oaf; a fool ...1968 Amer. sl.
• A.B. fools as a group (Asshole Brigade) ...1980s sl.
• ABRAM a gullible fool; a cuckold ...1639 UK sl.
• ACE a foolish or ineffectual person; a clumsy person; an oaf, a jerk: used sarcastically ...1969 US campus sl.
• ACROBAT a fool ...1958 W. Indies sl.
• ADDLE-BRAIN a stupid or half-witted fellow; a foolish bungler; a dullard ...1880
• ADDLE COVE a foolish man; an easy dupe ...Bk1898 Eng. dial.
• ADDLE-PATE a stupid bungler; a dullard; a weak, silly person; a foolish person; an easy dupe ...1601
• ADGER a foolish, silly person: used playfully to children ...Bk1905 Eng. dial.
• AH-AH a stupid person; a fool ...1928 Amer. dial.
• AIREDALE a fool; a worthless person; a pest ...1920s US sl.
• AIRHEAD a foolish person ...1972 sl., orig. & chiefly US
• AL a fool, a jester; a silly person ...1857 Eng. dial.
• ALEC a fool or simpleton ...1919 Aust. sl.
• ALECK a foolish person ...1944 Aust. sl.
• ALKITHOLE a foolish fellow ...1746 Eng. dial.
• ALKITOTLE a foolish fellow ...1746 Eng. dial.
• ALLYAUN a fool ...Irish sl.
• AMADAN a foolish person ...Irish sl.
• AMADAUN a foolish person ...Irish sl.
• AMATON a foolish person; one yielding to anger ...B1900 Sc.
• AMITAN a weak, foolish person ...Bk1911 Sc.
• AMOTH a big soft fool who would cry for nothing ...1878 Ireland
• ANIMAL a fool; an oaf; a stupid person ...L16
• APE † a foolish person who imitates ...c1330
• APPLEHEAD. a fool ...1940s US sl.
• APPLE-JOHN a foolish and probably impotent old man ...L16 sl.
• APPLE-KNOCKER a fool ...1930s sl.
• APPLE-PICKER a fool, an unsophisticated person, a country person ...1910s US sl.
• ARBUCKLE a fool ...20C teen & high school sl.
• ARSE a stupid, unpleasant, or contemptible person; a fool ...c1785
• ARSEHOLE, ASSHOLE a foolish or despicable person; an unpleasant person, usually male ...c1784
• ARSEWIPE (derogatory) a foolish or contemptible person ...1962 sl.
• ASS a foolish or stupid person ...c1450 colloq.
• ASSHEAD a stupid or foolish person; an idiot ...a1500 colloq.
• ASSINEGER a fool, a simpleton, a stupid person ...Bk1898 Eng. dial.
• ASSINEGO a fool, a simpleton, a stupid person ...Bk1898 Eng. dial.
• ASSNEGER a fool, a simpleton, a stupid person ...Bk1898 Eng. dial.
• ASSWIPE (derogatory) a foolish or contemptible person ...1953 sl. 
• ATTWOOD a foolish fellow; a stupid person; a blockhead; a simpleton ...1894 Eng. dial.
• AUF. AWF a foolish person, a simpleton ...1750 Eng. dial.
• BAARIE a fool; one who has newly arrived at a township from the countryside ...1977 S. Afr. sl.
• BABBY-LAKER one who entertains foolish speculations ...Bk1898 Eng. dial.
• BABE * an adult regarded as being like a child in some way; a childish or foolish person; an inexperienced, naive, or innocent person ...1542
• BABELAVANTE † a foolish or absurd person ...a1400
• BABION † (derogatory) a term of contempt for a person; a stupid or foolish person ...a1529
• BABOON (derogatory) a foolish, stupid, or contemptible person; a person considered to resemble a baboon in appearance; an ugly or uncouth person; an oaf, a jerk; often as a term of abuse ...1592
• BABY (often derogatory) an immature, foolish or childish person ...1539
• BACON-BRAINS a fool, a stupid clodhopper, a clownish blockhead ...a1634
• BADAUD a booby, a fool ...Bk1894
• BAFOON a term of abuse, a fool ...1989 sl.
• BAKE a fool, an idiot ...1860 US sl.
• BAKEBRAIN (derogatory) someone with limited or damaged mental faculties; a fool, an idiot; a stupid person ...1949 US sl.
• BAKEHEAD a fool, an idiot; a stupid person; an insane or crazy person  ...1949 US sl.
• BALDERDASH a fool ...1821 Anglo-Irish
• BALLITRAUNT † a foolish person; a buffoon; used as a term of contempt ...1790 Eng. dial.
• BALLOCKS a fool; a term of abuse; one who is performing or talking 'ballocks' or nonsense ...1916 sl.
• BALLOON a bully, a garrulous person, one full of hot air; a self-important or boastful idiot; a fool ...1965 Sc. & Irish English colloq.
• BALLOON-BRAIN a fool, a simpleton; a silly, empty-headed person ...1949 US sl. 
• BALLOON HEAD an arrogant, conceited, or stupid person; a fool, a simpleton, a silly, empty-headed person ...1931 colloq., chiefly US
• BALMY a fool, a simpleton; a soft, weak-minded person ...1887 Eng. dial.
• BAM a foolish, annoying, or obnoxious person; a belligerent or disruptive person; often used as a contemptuous form of address ...1959 Sc. colloq.
• BAMPOT a foolish, annoying, or obnoxious person; a belligerent or disruptive person; an eccentric person; often used as a contemptuous form of address ...1962 Sc. colloq.
• BAMSTICK a foolish, annoying, or obnoxious person; a belligerent or disruptive person; often used as a contemptuous form of address ...1965 Sc. colloq.
• BANANA BENDER a fool ...1992 UK sl.
• BANANAHEAD a simpleton, a fool, an idiot, a stupid person ...1949 US sl.
• BAPHEAD a fool ...2001 UK teen sl.
• BARBER a tediously talkative person; a fool, esp. in sports usage ...1927 US sl.
• BARI a fool; one who has newly arrived at a township from the countryside ...1970s S. Afr. sl.
• BARM-HEAD a soft, foolish person ...1865 Eng. dial.
• BARMPOT a foolish person ...1951 Brit. sl., orig. N. Eng. dial.
• BARMY a fool, a simpleton ...1887 Eng. dial.
• BARN-DOOR SAVAGE a countryman; a rustic; a yokel; a foolish, awkward, or clumsy person ...1876 sl.
• BARRIE, BARRY a fool; one who has newly arrived at a township from the countryside ...1977 S. Afr. sl.
• BASTOON a fool...1827 Irish sl.
• BAT a silly, foolish, thoughtless, or worthless person ...1870 US sl.
• BATBRAIN a fool or a crazy person ...1937 US sl.
• BATHEAD a fool or a crazy person ...1942 US sl.
• BATIE-BUM † (derogatory) a lazy or inactive fellow; an idler; a simpleton, a fool; a useless bungler ...1572 Sc. 
• BATIE-BUMMIL † an inactive helpless fellow; a useless bungler; a simpleton; a fool...a1550 Sc.
• BATTERLASH a small-witted person; a foolish or gullible person ...1867 Eng. dial.
• BAUBLE † a childish or foolish person; a silly trifler ...a1606
• BAVIAN * (derogatory) a fool, an idiot ...1797
• BAWCOCK a foolish person ...1795 Eng. dial.
• BAZIL † a drunkard, a sot; a fool ...1816 Sc.
• BAZOO a lout; a fool; an easy victim ...1929 US sl.
• BAZOOKA a fool ...1950 UK sl.
• BAZOONUS a lout; a fool ...1903 US sl.
• BAZZONUS a lout; a fool ...1929 US sl.
• B.B. a bird-brain; a fool, a stupid person; one of low intelligence; a slow-witted person ...1958 US sl.
• BB STACKER a stupid person; a fool ...1960 US sl.
• BEALS a fool, an idiot, an unsophisticated person; a displeasing person ...a2001 sl.
• BEAN a term of disparagement for a foolish, unpleasant or obnoxious person ...1915 US sl.
• BEANBRAIN a fool; a simpleton; a stupid oaf ...1953 US sl.
• BEANHEAD a dull, stupid person; a fool; an oaf ...1919 Amer. sl.
• BEARDLESS WONDER an incompetent or foolish person ...1952 US sl.
• BEAR'S ASS a fool; an ignoramus ...1969 US college sl.
• BEECHAM'S (PILL) a fool, a simpleton ...1952 Aust. rhyming sl. for 'dill'
• BEE EFF a foolish person, a 'bloody fool' ...1925 sl., orig. Brit. services' usage
• BEEF-BRAIN a thug; a fool ...1989 US sl.
• BEEFHEAD a thickhead, a blockhead, a fool ...1775
• BEE-IN-THE-BONNET an eccentric; a flighty person; a foolish person ...1856 Sc. & Eng. dial.
• BEERY BUFF a fool ...1960 UK rhyming sl. for 'muff'
• BEETLE a crazy, eccentric, or foolish person; a madman, an obsessive fan ...1605 sl.
• BEETLE-BRAIN (derogatory) a person of low intelligence; a stupid person; a blockhead; a fool; a dolt ...1593
• BEETLEBROW a blockhead; a fool ...1850 sl.
• BEETLE-HEAD (derogatory) a person of low intelligence; a blockhead; a fool, a stupid person ...1577
• BEGUNK a fool ...1895 Sc.
• BEHEMA a fool ...Bk1982 Jewish
• BEL-SHANGLE a fool ...1847 UK sl.
• BEN a simpleton, a fool ...c1698 UK criminals' sl.
• BEND a foolish, foppish fellow ...Bk1898 Sc.
• BERK a despicable person; a stupid or offensive person; a disliked person; a fool ...1929 Brit. rhyming sl. for 'cunt' (Berkeley Hunt)
• BERKELEY (HUNT) a fool; a person whom one does not like; an incompetent ...1937 Brit. rhyming sl. for 'cunt'
• BERKSHIRE HUNT a fool; a person whom one does not like ...1960 Brit. rhyming sl. for 'cunt' 
• BESOM-HEAD a foolish or stupid person; a blockhead ...1864
• BEZOM-HEAD a foolish, stupid person ...1889 Eng. dial.
• B.F. a foolish person, a 'bloody fool' ...1894 sl.
• BIFF a fool ...2003 UK sl.
• BIG BLAH a fool; an idiot ...1927 US sl.
• BIG BOY a foolish, reckless, devil-may-care young man; a loveable idiot ...1922 US Black sl.
• BIG-BWOY an affectionate term for a foolish person ...1995 W. Indies
• BIG CHEESE - a foolish, obnoxious, or inept person; anyone who has pretensions to being smart ...1918 US sl.
• BIG STIFF a term of abuse; a fool; a rough, clumsy, stupid, or overbearing man; a mean, disagreeable or contemptible person; a disliked person; an uncouth, self-opinionated person ...1896 sl., orig. US
• BILLY a fool ...1786 Sc. & UK criminals' sl.
• BILLY BARLOW a half-witted street fool; a street clown; a mountebank ...1835 UK sl.
• BILLY BUTTON a gullible fool, esp. one who performs a job of work without first making sure that they will be paid ...1996 W. Indies rhyming sl. for 'gets nothing'
• BILLYGOAT an incompetent, silly person; a fool ...Bk1988 Aust. sl. 
• BILLY-MINAWKY a foolish or stupid fellow, a booby ...Bk1887 Eng. dial.
• BILLY MUGGINS a fool ...1910s Aust. sl. 
• BILLY-WHIFFLER a fool; a simpleton ...Bk1898 Eng. dial.
• BINLID a stupid person; a fool ...Bk1997 Ulster sl.
• BIRD-BRAIN a person with a small brain; one of low intelligence; a frivolous, scatterbrained person; a fool; a stupid person ...1933
• BIRK a fool; a stupid or slow-thinking person ...1929 sl.
• BISH a fool, a stupid person, a dope ...1963 US teen sl.
• BIZZUM-HEAD a person who is equally foolish and stupid ...Bk1855 Eng. dial.
• BLADDER MOUTH a coarse, noisy talker, devoid of sense; a noisy fool ...Bk1886 Eng. dial.
• BLADDERSKATE a silly foolish person; a babbler ...a1680 Sc.
• BLADDERSKYTE a silly foolish person ...Bk1876 Sc.
• BLAH a fool, an idiot ...1923 US sl.
• BLAITIE BUM † (derogatory) a lazy or feckless person; an idler; a simpleton, a fool, a bungler; a sheepish fellow ...1540 Sc.
• BLEEDER a 'bloody fool' ...1890 sl.
• BLELLUM a foolish, talkative person; an idle chatterer ...1787 Sc.
• BLOB a foolish person ...1916 sl., chiefly Aust.
• BLOCK a fool, an idiot, a stupid person ...M16 sl.
• BLOCKHEAD a foolish person ...1549
• BLUNNERBOAR a blundering fool ...Bk1911 Sc.
• BOGAN a fool, an idiot ...Aust. sl.
• BOINARD † a fool, a simpleton; a rogue, a rascal, a scoundrel, a low person; a term of reproach ...a1300
• BOOB a foolish person ...1907 sl.
• BOOBY a foolish person ...1599 sl.
• BOOFHEAD a fool; a very gullible person ...c1930 Aust. sl.
• BORN-HEAD a young precocious fellow; a very foolish person ...Bk1911 Sc.
• BOSTHOON a fool or blockhead ...1914 Irish sl.
• BOSTOON a fool or blockhead ...1914 Irish sl.
• BOZO a clumsy, clownish, or foolish fellow; an oaf; a rude or annoying person ...1916 Amer. sl.
• BRACK-BRAIN a fool ...Bk2006 US sl.
• BROWNMOUTH a talkative fool ...1991 Irish sl.
• BUFFER a foolish old person ...1749 Brit. sl.
• BUFFLEHEAD a fool, a blockhead, a simpleton, a stupid person, a silly person, an ignoramus ...1659
• BUGGERLUGS an annoying or foolish person; chiefly used as an affectionate form of address, or mild term of reproof ...1861 sl.
• BURG a fool, an idiot; an unpleasant person ...1980s S. Afr.
• BURK(E) a foolish person ...1936 sl., chiefly Brit.
• BUTTERBRAIN a fool ...1975-78 Amer. sl.
• BUTTERED BUN a country fool; a rustic simpleton ...E18 sl.
• BUTTERHEAD a fool ...1963 US sl.
• BUTTHOLE a foolish or despicable person; an obnoxious person ...1962 Amer. sl.
• BUZZARD a foolish or despicable person; a contemptible old man ...1641
• CA a soft, foolish person ...1825 Sc. 
• CABBAGE-HEAD a fool; a soft-head; a stupid person ...1682 sl.
• CAKE a fool or dullard; a stupid fellow ...1785 Eng. dial. & sl.
• CAKEHEAD an idiot; a fool ...1998 UK sl.
• CAKEY a fool or dullard ...L18 sl.
• CAKUM a foolish person ...Bk1898 Eng. dial.
• CALF a fool, a simpleton; a stupid or loutish person; an awkward or silly boy or man; a meek, harmless person ...1553 sl.
• CALF-HEAD a foolish fellow ...Bk1898 Eng. dial.
• CALF'S HEAD a fool; a very stupid fellow ...L16 sl.
• CALONKUS a fool ...L19 Aust. sl.
• CANG † a fool ...a1225
• CANK † a fool ...a1225
• CARLE-GROPUS † a stupid person; a fool ...1866 Sc.
• CARTOON a ridiculous person; a fool ...1927 Amer. sl.
• CATHEAD a fool ...1950s US sl.
• CEMENTHEAD a blockhead, a fool, a stupid person ...1949 Amer. sl.
• CHANG † a fool ...a1225
• CHANK † a fool ...a1225
• CHARLEY, CHARLIE a foolish person ...1946 sl., chiefly Brit.
• CHEESEHEAD a fool; a stupid person ...20C teen & high school sl.
• CHEESE MEISTER  a fool; a jerk ...20C teen & high school sl.
• CHERRY PICKER an ignorant rustic; a fool ...1929 US sl.
• CHICKENBRAIN a fool ...1922 US sl.
• CHICKEN'S HEAD a fool ...1960s US Black sl.
• CHIEF a general insult; a fool, a braggart ...1990s UK Black sl.
• CHOOCH a blockhead, a fool ...1971 Italian-American
• CHOWDAR a fool ...Bk1892 Anglo-Chinese
• CHOWDERBRAIN a fool, a stupid person ...1960 US sl.
• CHOWDERHEAD a stupid person, a fool, a blockhead; a muddle-headed person; a dunce ... 1682 sl.
• CHUCKLEHEAD a fool; a silly person; a stupid person ...1731
• CHUMP a fool; a soft-head; anyone gullible or easily taken in ...1682 sl.
• CHUMPIE a fool; anyone gullible or easily taken in ...L19 sl.
• CHUMP OF WOOD a fool; a soft-head ...Bk1891 sl.
• CHUPIDEE, CHUPIDDY, CHUPIDIE, CHUPIDY a gullible, ignorant fool ...20C W. Indies sl.
• CLODPOLE, CLODPOLL a foolish person ...1601 Brit.
• CLOT a fool; an oaf ...19C colloq.
• CLOT-HEAD a fool; an oaf ...19C colloq.
• CLOUTER-HEAD a foolish, stupid person; one deficient in understanding ...c1861 Eng. dial.
• CLUCK a stupid oaf; a fool ...20C US colloq.
• CLUNK a foolish person ...1942 US sl.
• COCK-A-LILTY a person talking or acting foolishly ...19C Eng. dial.
• COCKAMAMIE, COCKAMAMY a foolish or ridiculous person ...1936 US sl.
• COCKAMANIE, COCKAMANY a foolish or ridiculous person ...1936 US sl.
• COCKSCOMB a fool; a fop or dandy ...L16
• COD a fool ...L17 sl.
• CODFISH a fool ...L18 sl.
• COD'S-HEAD a stupid fellow, a fool, a blockhead; a dupe ...1566
• COD'S HEAD AND SHOULDERS a dupe; a fool ...19C sl.
• COISTRIL, CUSTREL * a worthless or contemptible person; a knave, a rogue; later, a cowardly or timorous person; a foolish or inexperienced youth ...1570 arch.
• COKES a fool ...M16 sl.
• CONEHEAD a fool; an oaf ...Bk2006 US sl.
• COOT a foolish or crotchety person, esp. one who is old ...colloq.
• COXCOMB a fool; a fop or dandy ...L16
• CRACKBRAIN a fool; a stupid oaf ...Bk2006 US sl.
• CRACKERJACK a fool, an oaf ...1970s US campus sl.
• CRATEHEAD a fool, an idiot ...Bk2004 sl.
• CUTER a fool; a josh ...Bk1914 criminals' sl.
• D.A. a fool, an idiot (Dumb-Ass) ...1970s US campus sl.
• DACEHEAD a fool ...E19 sl.
• DAFF † one deficient in sense or in proper spirit; a simpleton, a fool; a coward ...c1325 obs. exc. N. Eng. dial.
• DAFFAM a fool, a silly person ...Bk1828 Eng. dial.
• DAFFE † a stupid, foolish person ...c1325
• DAFF(E)Y a fool, a silly person ...1867 Eng. dial.
• DAFT DORIS a foolish woman ...2000 UK sl.
• DAFT-HEAD a silly fellow; an idiot; a fool ...Bk1873 Eng. dial.
• DAFTIE a simpleton; a fool ...1868 Sc. & Eng. dial.
• DAFT WATTY a silly, awkward person; a foolish fellow; a blockhead ...1805 Eng. dial.
• DAMFOOL a damned fool ...c1880 colloq.
• DAMN-FOOL a damned fool ...19C colloq.
• DAMPHOOL(E), DAMPHULE a damned fool ...c1880 colloq.
• DAMWIT a fool ...1940s US sl.
• DAN a fool (Dumb-Ass Nigger) ...2000s US Black sl.
• DAPHNE a foolish woman ...1980s Aust. sl.
• DARB a fool ...1920s sl.
• DARK a fool; a dullard ...1960s US campus sl.
• DASIBERD † a stupid fellow, a fool, a dullard, a simpleton ... c1400
• DATE a foolish, silly, stupid, or weak person ...1914 UK sl.
• DAW † a silly, chattering person, a simpleton, a fool ...c1500 obs. exc. Eng. dial.
• DAWCOCK † a stupid, silly, awkward fellow, a simpleton, a fool ...1556 obs. exc. Eng. dial.
• DAWKIN a dull, stupid person, a simpleton, a fool ...1565 Eng. dial.
• DAWPATE † a silly fellow, a simpleton, a fool ...a1529
• DEADHEAD a fool; a stupid person ...1930s Black sl.
• DEAD ONE a fool ...L19 US sl.
• DICKEY-DIDO an idiot; a fool...19C Brit. sl.
• DICK-HEAD a foolish person ...1964 sl.
• DILBERRY a fool ...1952 NZ sl.
• DILL a fool ...1941 Aust. sl.
• DILLPOT a fool ...1941 Aust. rhyming sl. for 'twat'
• DILLYPOT a fool ...1941 Aust. rhyming sl. for 'twat'
• DIMELOW a fool, an idiot ...1900 UK sl.
• DIMWIT a slow-witted fool ...1921 US sl.
• DINDERHEAD a foolish person ...1867 Eng. dial.
• DINELO, DINELOW a fool, an idiot ...1900 UK sl.
• DING-A-LING a fool; an oaf; an odd, giddy person who hears bells ...1935 US sl.
• DINGBAT a dull, stupid person; a fool; a silly or light-headed person ...1915  Amer. dial.
• DINGDONG a dull, stupid person; a fool; an oaf; a silly or light-headed person ...1929 Amer. sl.
• DINGLEBERRY a foolish person ...1924 sl., orig. US
• DINGLEBODY a foolish, simple person ...1957 US sl.
• DIP a foolish person ...1932 US sl.
• DIPSHIT a foolish person ...1962 US sl.
• DIPSTICK an inept fool; an idiot; a jerk; a stupid or contemptible person; an oaf ...1963 US sl.
• DIRK a foolish, peculiar, or obnoxious person; an absent-minded or inattentive person; a jerk ...1964 US sl.
• DIVVY, DIVY a foolish person ...1989 Brit. sl.
• DIZ, DIZZ a foolish person ...1963 US sl.
• DIZZARD † a foolish, stupid, or silly fellow; an idiot, a blockhead; a weak-minded person ...1547 obs. or arch.
• DOBBIE a stupid fellow; a blockhead, a fool, a simpleton, a dolt; a childish old man, a dotard; an awkward fellow, a clown ...1677 Sc. & Eng. dial.
• DODDY-PATE † a stupid person, a blockhead, a fool, a dunce ...c1500 obs. exc. Eng. dial.
• DODE a fool ...1989 US sl.
• DODO a fool; an unintelligent person ...1898 US colloq.
• DOE a fool, a simpleton, a dupe ...1961 US sl.
• DOES (taboo) a foolish or despicable person ...S. Afr. sl.
• DOITARD a simpleton, a fool, an idiot ...1860 Eng. dial.
• DOITY a fool, simpleton, idiot ...19C Eng. dial.
• DOLLYPOT an oaf; a fool ...1920s Aust. rhyming sl. for 'twat'
• DONKEY a foolish person ...Bk1913-17 Amer. dial.
• DOOBIE a dull, stupid fellow; a fool, a simpleton; a dunce ...19C Sc.
• DOODLE-BRAIN a general insult; a stupid person, a fool ...1990s Aust. teen sl.
• DOODLE-HEAD a general insult; a stupid person, a fool ...1990s Aust. teen sl.
• DOOF a fool, a simpleton, an oaf ...1970s US sl.
• DOOFUS an oaf, a fool ...M20 US sl.
• DOORKNOB a fool ...1930s sl.
• DOPE a foolish person ...1851 sl.
• DORK a foolish person ...1967 sl., chiefly US
• DORKUS a fool ...1979 US sl.
• DORKUS MAXIMUS a simpleton; a great fool ...Bk2006 US sl.
• DOTARD a weak-minded or foolish old person ...a1393
• DOUGH-HEAD a fool ...Bk1905 Amer. dial.
• DRONGO a stupid, foolish, or incompetent person ...1941 Aust. & NZ sl.
• DROOB a stupid fool ...Bk1999 Aust. sl.
• DROOP an ineffectual, incompetent, or languid person; a fool ...1932 US sl.
• DUCK EGG a fool ...2003 UK sl.
• DUDE a foolish or obnoxious fellow ...1967 US sl.
• DUDHEAD a fool, a dolt ...1963 US sl.
• DUFFER an incompetent person; a person of no ability; a foolish oaf; a bungler ...c1730 UK sl.
• DUFFUS a fool, a dolt, an oaf ...1978 US sl.
• DULL-HEAD † a dull-headed or slow-witted person; a fool, a blockhead ...1534
• DULL-PATE † a dull-headed or slow-witted person; a fool, a blockhead ...a1500
• DUMB a foolish or stupid person ...1928 US sl.
• DUMB-ASS a foolish person ...1958 US sl.
• DUMB-BELL a foolish person ...1918 sl., orig. US
• DUMB BUNNY a foolish person ...1921 sl., orig. US
• DUMB-BUTT a foolish person ...1973 US sl.
• DUMB CLUCK a stupid oaf; a person as stupid as a chicken; a fool ...1906 Aust. & US colloq.
• DUMB DORA a foolish woman or girl ...1922 sl.
• DUMB-DUMB, DUM-DUM a foolish person ...1937 sl., orig. Amer.
• DUMBFUCK a foolish person ...1949 US sl.
• DUMBHEAD a foolish person ...1887 sl., chiefly US
• DUMBKOPF a foolish person ...1809 sl., orig. US
• DUMBO a dolt, a fool; a large and stupid oaf ...1932 US sl.
• DUMBSHIT a foolish person ...1961 US sl.
• DUM-DUM a foolish person ...1937 sl., orig. Amer.
• DUMKOPF, DUMMKOPF a foolish person ...1809 sl., orig. US
• DUMMOCK a fool, a blockhead ...19C Eng. dial.
• DUMMY a foolish person ...1796 sl.
• DUNCECOMB † a stupid person; a fool; a dim-witted person; a dunce ...1612
• DUNDERHEAD (depreciative) a stupid, slow-witted person; an idiot; a fool ...1630
• DUNDERPATE (depreciative) a stupid or foolish person ...1697 arch.
• DUNDERWHELP (depreciative) a stupid or foolish person ...a1625 arch.
• DWEEB a person held in contempt, esp. one ridiculed as studious, puny, or unfashionable; a fool ...1982 US sl.
• ECHOHEAD a foolish person, usually female ...1990s sl.
• EGG a foolish, ineffectual, or obnoxious person ...1918 US sl.
• EGG-FOR-FUCK a fool, a simpleton, an obnoxious person ...1990s US college sl.
• EGGHEAD a fool, a dolt, an idiot ...1941 US sl.
• EGGNOG a foolish or obnoxious person ...c1921 US sl.
• EGGO a fool, a misfit ...1980s US college sl.
• ESEL, EZEL a fool, a simpleton ...1910s S. Afr. sl.
• FART a fool, an unpleasant person, often older than the speaker ...M18 sl.
• FART-ARSE a term of contempt; a fool; an incompetent ...1940s sl.
• FARTHOLE a contemptible person ; an obnoxious or foolish person ...1970 Amer. sl.
• FAT-BRAIN a fool, an idiot; often used affectionately as well as derogatorily ...L16 sl.
• FAT-HEAD a fool, an idiot; often used affectionately as well as derogatorily ...1842 sl.
• FEATHER-BRAIN a foolish, giddy person; a dull, stupid person; a silly, light-headed person ...1839
• FILBERT a foolish, eccentric, or crazy person ...1915 Amer. sl.
• FISH a person easily fooled; a fool, an oaf ...20C US sl.
• FISH IN THE POOL a fool ...1998 Brit. rhyming sl.
• FLAKE one who is 'flaky' or liable to act in an eccentric or crazy manner; also, a foolish, slow-witted or unreliable person ...1968 sl.
• FLAT a fool; a soft-head ...Bk1891 sl.
• FLAT-HEAD a foolish person ...1862 sl.
• FLAT TIRE a fool, an oaf; a worthless man ...E20 US sl.
• FLEAK (derogatory) a woman; a foolish or giddy woman ...E17 Brit. colloq.
• FLURT an insignificant person; a fool ...19C Eng. dial.
• FLY-FLAT a clever fool ...1864 sl.
• FOOD FOR THE SQUIRRELS a stupid or foolish person ...Bk1974 Amer. sl.
• FOO-FOO a fool, a worthless person ...Bk1974 Amer. dial.
• FOOL KILLER a notional creature called upon to dispose of fools ...1853 US sl.
• FOOL-FOOL a simple-minded fool ...1994 Jamaica
• FOOLIO a fool; a social outcast ...1994 US sl.
• FOOZLE a man who is easily humbugged; a fool ...Bk1892 Amer. sl.
• FOPDOODLE † a silly, vain, empty person; a stupid or insignificant fellow; a fop, fool, simpleton ...a1600
• FRIP a dull, foolish, or stupid person ...1970 US college sl.
• FUCKWIT a foolish person ...1969 sl., orig. Aust.
• FUNGE † a person lacking intelligence or common sense; a fool ...1621
• FUTZ a foolish or unpleasant person ...1935 US sl.
• FUTZER a foolish or unpleasant person ...1938 US sl.
• FUZZBRAIN a foolish person ...1969 US sl.
• GAABY a fool; a dolt ...Bk1869 Eng. dial.
• GABBERLOONEY one who talks too much, acts the fool ...Bk1997 Ireland sl.
• GABBY a stupid or foolish person; an idiot; a simpleton ...1926 US sl.
• GABES a foolish person, one who acts foolishly; a busybody ...Bk1900 Eng. dial.
• GABES-CHANY a foolish person, one who acts foolishly; a busybody ...Bk1900 Eng. dial.
• GABEY, GABY - a stupid or foolish person; an idiot; a fool ...1746 colloq. & Eng. dial.
• GABSHITE a fool; a dupe ...1966 sl.
• GADAHA a fool, an idiot ...1964 W. Indies
• GADGIE a fool, an idiot ...1985 Sc. sl.
• GADSO a fool ...17C sl.
• GAFONE (derogatory) an Italian; a fool ...1976 sl.
• GAG a fool, a laughingstock ...1840 US
• GAIBIE a stupid, foolish person; a blockhead, a simpleton, a fool, a lout ...1790 Sc.
• GAISLING † a foolish, inexperienced person; a term of disparagement to a child ...1819 Sc.
• GAKEM a stupid fellow; a fool ...Bk1895 Eng. dial.
• GAKEY a left-handed person; an awkward, ungainly, clumsy person; a fool; a simpleton; a lout, a bumpkin ...1726
• GALAH a foolish person ...1938 Aust. sl.
• GALIMAVIS a fool, a stupid person ...1925 Sc.
• GALLOOT, GALOOT a man, esp. if hulking, stupid, boorish, foolish, clumsy, or otherwise objectionable; an awkward or uncouth person ...1818 UK
• GALLOWS-FOOL an arrant fool, one that deserves hanging ...1894 Eng. dial.
• GAM a lout, a simpleton, a fool ...1966 Irish sl. 
• GAMALEERIE a foolish, clumsy person; an old dotard ...1880 Sc.
• GAMARAMUS † a fool, a nitwit ...1849 Sc.
• GAMAREERIE, GAMMEREERIE a foolish, clumsy person ...1880 Sc.
• GAMAWOW † a fool ...1825 Sc.
• GAME † a person marked out to be cheated or fooled; a fool, a simpleton, esp. a victim ...1699 criminals' sl.
• GAMERAL, GAMMEREL a fool; a stupid fellow; a dunce; a silly lout ...1826 Eng. dial.
• GAMERAMUS † a fool, a nitwit ...1849 Sc.
• GAMF a buffoon, a fool; an empty-headed fellow who makes a great deal of noisy mirth; a fool, or one who wishes to seem so ...1825 Sc.
• GAMFRAL, GAMFREL, GAMFRIL * a stupid or foolish person; a blockhead, an idiot; a forward, presumptuous person ...1729 Sc.
• GAMFUL a fool, a buffoon ...20C sl.
• GAMMERSTAGS a rude, wanton girl; an idle, loose girl; a foolish girl ...1788 Eng. dial.
• GAMMERSTANG a rude, wanton girl; an idle, loose girl; a foolish girl ...1788 Eng. dial.
• GAMMERSTEL a rude, wanton girl; an idle, loose girl; a foolish girl ...1788 Sc.
• GAMMY a fool ...1892 Aust. sl.
• GAMPH a fool, a buffoon; an empty fellow who makes a great deal of noisy mirth ...1825
• GAMPHREL(L) a fool; a stupid or senseless fellow; a blockhead ...1728 Sc.
• GANCH an awkward, silly fellow; a fool; a boor; an ignoramus; someone who behaves badly ...Bk1880 N. Ireland
• GANDER a dull or stupid person; a fool, a simpleton; a gawky person ...1553
• GANK a fool, an easy mark; a dupe ...Bk2006 Amer. sl.
• GAPESNATCH a fool, a stupid person ...Bk1868 Eng. dial.
• GAPIE a stupid, gaping, or irresponsible person; a fool ...1908 Sc.
• GAPPER-MOUTH a fool; a simpleton ...1886 Eng. dial.
• GAPPY a stupid, gaping, or irresponsible person; a fool ...1908 Sc.
• GAPSHLY a simpleton, a fool ...1896 Eng.dial.
• GAPUS a fool, a simpleton, a silly fellow; one who is noisily foolish ...1825 Sc.
• GASOB a fool, a simpleton, a blunderer ...1906 Aust. sl.
• GAUBSHITE an awkward, ill-kept, dirty person; a filthy, slovenly man; a boor, a fool, a blockhead ...Bk1887 Eng. dial.
• GAUBY a simpleton, a fool, a dolt, a lout, an oaf  ...Bk1869 Eng. dial.
• GAUCUM a fool, a simpleton, a booby; a stupid, clumsy fellow ...1846 Eng. dial.
• GAUCUS a fool ...1954 Sc.
• GAUK an awkward, clumsy person; a fool; a simpleton ...1850 Sc. & Eng. dial.
• GAUKAMOUTH a gaping fool ...Bk1886 Eng. dial.
• GAUKIE 1. an awkward, clumsy person; a fool; a simpleton; an idiot ...1726 Sc.
2. a foolish, forward, vain woman ...Bk1900 Sc.
• GAUKUM a fool, a simpleton, a booby; a stupid, clumsy fellow ...1846 Eng. dial.
• GAUKY an awkward, stupid, badly-mannered person; an oaf; an awkward fool; a simpleton who stares vacantly ..Bk1828 Eng. dial.
• GAUM a painfully stupid or gullible person; a fool ...1837 sl., orig. Irish
• GAUMBLIN a fool; a simpleton; a greenhorn ...1840 Eng. dial.
• GAUMERIL a fool; a stupid fellow; a dunce; a silly lout ...1826 Sc. & Eng. dial.
• GAUMLESS - stupid, half-witted person; a fool ...1896 Eng. dial.
• GAUMLESS-HEAD a stupid, half-witted person; a fool ...1896 Eng. dial.
• GAUMRIL a fool; a stupid fellow; a dunce; a silly lout ...1826 Eng. dial.
• GAUMUCK a stupid person; a fool ...1890 Eng. dial.
• GAUNCH an ignoramus; someone who behaves badly; a fool; a boor ...1997 Ulster sl.
• GAUP a fool or simpleton, a stupid person; one who gapes rudely ...1825 Sc. & Eng. dial. & colloq.
• GAUPIE a fool or simpleton, a stupid person; one who gapes rudely ...1880 Sc.
• GAUPUS a stupid, silly person, a simpleton; a fool; a clumsy lout; an open-mouthed, vacant-minded person, esp. one given to talking much and foolishly ...1808 Sc. & Eng. dial.
• GAUPY a vacant, staring person; a fool, a blockhead, a simpleton; a stupid or silly person ...1856 Sc. & Eng. dial.
• GAUSTER a violent, unmanageable fellow; a swaggering fellow; a fool ...1815 Sc. & Eng. dial.
• GAUVERIL an awkward, foolish fellow ...Bk1900 Eng. dial.
• GAUV(E)Y a fool, a simpleton, a dunce; a half-witted person; a vacant-minded person, one that is easily imposed upon ...1796 Eng. dial.
• GAUVISON an awkward, gaping fellow; a fool, a simpleton, a silly, staring fellow, a blockhead; a dunce; on easily imposed upon ...1788 Eng. dial.
• GAVON (derogatory) an Italian; a fool ...1976 sl.
• GAVONE (derogatory) an Italian; a fool ...1968 sl.
• GAVYSON an awkward, gaping fellow; a fool, a simpleton, a blockhead; a dunce ...1788 Eng. dial.
• GAWBY a stupid or foolish person; an idiot; a blockhead; a simpleton; a lout ...1746 colloq. & Eng. dial.
• GAWCUM an awkward, ungainly, clumsy person; a fool; a simpleton ...Bk1825 Eng. dial.
• GAWK an awkward, clumsy, stupid person; a fool; a simpleton; a lout, a bumpkin, an uncultivated person; a dupe ...1685
• GAWK-A-MOUTH a gaping fool; one who stares vacantly ...1777 Eng. dial.
• GAWKER a gaping fool; one who stares vacantly ...Bk1900 Eng. dial.
• GAWKEY, GAWKIE, GAWKY a left-handed person; an awkward, ungainly, clumsy person; a foolish, gaping person; a simpleton; a lout, a bumpkin ...1726
• GAWK-HAMMER a gaping fool; one who stares vacantly ...1872 Eng. dial.
• GAWK-HEAD a foolish, awkward person ...Bk1876 Eng. dial.
• GAWKUM a fool, a simpleton, a booby; a stupid, awkward, clumsy fellow; a lout ...1846 Eng. dial.
• GAWKUMY a fool, a simpleton, a booby; a stupid, clumsy fellow; a lout ...1846 Eng. dial.
• GAWKUS a fool ...1954 Sc.
• GAWM a painfully stupid or gullible person; a fool; a simpleton; a lout ...1837 sl., orig. Irish
• GAWMBLIN a fool; a simpleton; a silly fellow; a greenhorn ...1840 Eng. dial.
• GAWMEREL a fool; a stupid fellow; a dunce; a silly lout ...1826 Eng. dial.
• GAWMOGE a painfully stupid or gullible person; a fool ...Bk1910 Ireland English
• GAWN(E)Y a fool; a simpleton; a stupid, awkward person ...1777 Eng. dial. 
• GAWNICUS a fool, a dolt, a stupid fellow, an ignoramus, a simpleton ...1867 Amer. dial.
• GAWP a fool or simpleton, a stupid person; one who gapes rudely ...1825 Sc. & Eng. dial.
• GAWPIE a fool or simpleton, a stupid or silly person; one who gapes rudely; one who laughs without reason ...1825 Sc.
• GAWPSHEET an awkward, ill-kept, dirty person; a fool, a blockhead ...Bk1887 Eng. dial.
• GAWPUS a stupid, silly person, a simpleton; a fool; a blockhead; a clumsy lout; an open-mouthed, vacant-minded, staring person, esp. one given to talking much and foolishly ...1808 Sc. & Eng. dial.
• GAWVISON a silly, awkward, gaping fellow; a noisy, foolish person; a simpleton, a blockhead; a half-witted person; a dunce ...1788 Eng. dial.
• GAWVY a fool, a simpleton; a half-witted person; an open-mouthed fellow ...Bk1877 Eng. dial.
• GAZAYBEE a fool ...1983 Irish sl.
• GAZEBO a fool ...1983 Irish sl.
• GAZINK a  fool ...1922 US sl.
• GAZOB a foolish person ...1906 Aust. sl.
• GAZOO a fool; a stupid or unpleasant person; a lout, a boor ...1914 UK sl.
• GAZOOB a fool, a simpleton, a blunderer ...1906 Aust. sl.
• GAZOOK a fool; a stupid or unpleasant person; a loud lout, a boor; a clumsy oaf; an ineffectual or incompetent person ...1901 US sl.
• GAZOOKUS a fool; a stupid or unpleasant person; a lout, a boor ...1924 US sl.
• GAZOONEY, GAZOONIE, GAZOONY - a boy or lad; an inexperienced youth; a foolish, ignorant or eccentric fellow; a naive person ...1914 US sl.
• GAZOOP a fool; a stupid or unpleasant person; a lout, a boor ...1901 US sl.
• GAZOOPUS a fool; a stupid or unpleasant person; a lout, a boor ...1933 US sl.
• GAZUNY an amusing person; a fool ...1917 US sl.
• G.D.F. a God-Damned Fool ...1917 US sl.
• GECK † a fool, a simpleton, a dunce; a stupid, clumsy fellow; one who is befooled or derided, one easily imposed on, a dupe ...c1530 obs. exc. Eng. dial.
• GEEK a person, a fellow, esp. one who is regarded as foolish, offensive, worthless, etc.; a clumsy or eccentric person; one who is befooled or derided; a dupe ...1876 sl., orig. N. Eng. dial.
• GEEK-A-MO a geek; a fool ...1991 US surfing sl.
• GEIT a foolish fellow, an idiot; a madman ...Bk1900 Sc.
• GEKE † a fool, a simpleton; one who is befooled or derided, a dupe ...1515 obs. exc. Eng. dial.
• GELLYHEAD a fool ...1992 NZ sl.
• GERBIL a stupid, insignificant, or unpleasant person; a foolish or obnoxious person ...1986 US sl.
• GET(T), GHET an idiot; a fool; an unpleasant or despicable person; a term of abuse ...1931 UK sl.
• GETSIE an idiot; a fool; an unpleasant person; a term of abuse ...1935 UK sl.
• GEUP a foolish person ...1950 Sc.
• GHOMEY a painfully stupid or gullible person; a fool ...1837 sl., orig. Irish
• GIBLET a stupid, foolish, or inept person ...1984 US sl.
• GIBONEY a stupid, foolish, or offensive person; also, a hired thug, a hoodlum; broadly, a man, a fellow ...1921 Italian-American sl.
• GIDDY GERTIE a foolish female ...Bk1945 jive usage
• GIDDY GOAT an irresponsible fool ...Bk1958 Eng. sl.
• GIG a fool, a simpleton, an idiot, a stupid person; a trifling, silly, flighty fellow ...1685 Eng. dial.
• GIG APE a fool; an idiot ...1948 Aust. sl.
• GIGHEAD a fool, an idiot ...1940s Aust. sl.
• GILL a gullible or credulous person; a fool ...1592
• GILLIE, GILLY a rather stupid, foolish or silly person; a simpleton ...1770
• GILLIEGACUS, GILLIGACUS, GILLY-GACUS * a foolish or silly person; a simpleton ...1719 Sc.
• GILLIEGAPUS, GILLY-GAPUS * a foolish or silly person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GILLIEGAUKIE, GILLIE-GAWKIE, GILLY-GAUKIE, GILLY-GAWKIE * a foolish or silly person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GILLIEPEROUS  a stupid fool ...1935 Sc.
• GILLY-GAUPIE, GILLY-GAWPIE, GILLY-GAWPY - * a foolish or silly person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GILLY-GAUPUS, GILLY-GAWPUS - * a foolish, silly, or half-witted person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GILLY-GAWKER - * a foolish or silly person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GILLY-GAWPOCK - * a foolish or silly person; a simpleton; a person who is lanky, awkward, or stares stupidly ...1719 Sc.
• GIMMICK a foolish, peculiar, or eccentric person; one who has been mulcted by cults, healers, fortune-tellers, or mystics ...1926 US sl.
• GIMP (derogatory) a stupid, foolish, unpleasant, obnoxious, or contemptible person; a simpleton; an incompetent or weak person ...1924 sl., orig. US
• GIMPY (derogatory) a stupid, foolish, unpleasant, obnoxious, or contemptible person ...1959 US sl.
• GINK (often derogatory) a fellow; a guy; esp. an odd, eccentric, or foolish man; a stupid or useless person; someone who is unworldly or socially inept ...1906 sl., orig. US
• GIPE, GYPE a fool, an idiot ...1825 Sc.
• GIT a fool, an idiot, a dolt; a worthless person, a good-for-nothing ...1858
• GITE a foolish fellow, an idiot; a madman ...Bk1900 Sc.
• GIZMO a foolish or inconsequential man ...1942 US sl., esp. Navy usage
• GLADDIE a fool ...1892 Eng. dial.
• GLAVER one who is addicted to idle, foolish gossip; an idle, foolish person ...1825 Sc. & Eng. dial.
• GLEEP an odd, obnoxious, or foolish person; a stupid person; an oaf; a disliked person ...1947 US college sl.
• GLOCK a fool; a half-witted person; an eccentric person ...1886 UK sl.
• GLOFFUS a rough, uncouth person of noisy, foolish, or light-headed behaviour, often referring to one of ugly or unprepossessing appearance ...1866 Sc.
• GLOIK a fool, a simpleton; applied to a woman ...1950 Aust. sl.
• GLOIT a fool, a simpleton; applied to a woman ...2005 Aust. sl.
• GLOM a fool, a stupid person; an awkward person; a worthless or inept person; a dunce ...1930 US sl.
• GLOP a fool ...1864 Eng. dial.
• GLOWT a fool, a blockhead; a clumsy fellow ...Bk1878 Eng. dial.
• GLOW-WORM a term of contempt; a foolish person ...1624
• GLUEHEAD a fool ...1839 UK sl.
• GLUFFIS, GLUFFUS a rough, uncouth person of noisy, foolish, or light-headed behaviour, often referring to one of ugly or unprepossessing appearance ...1866 Sc.
• GLUMF a sulky fool ...Bk1876 Sc.
• GLUNDIE, GLUNDY † an inactive, awkward, or clownish person; a fool; a stupid person ...1824 Sc.
• GLUNNY † an inactive person; a fool; a stupid person ...1825 Sc.
• GLYORACH a fool; a blockhead ...1936 Sc.
• GNAW-POST a stupid, ignorant person; a silly fellow; a fool, a simpleton ...1856 Eng. dial.
• GO-ALONG a fool; a soft-head ...Bk1891 sl.
• GOAT a foolish person ...1916 sl.
• GOBALOON one who talks too much, acts the fool ...20C Ireland sl.
• GOBBERLOONY one who talks too much, acts the fool ...20C Ireland sl.
• GOBDAW a foolish person ...a1966 Anglo-Irish
• GOKY †* a fool, a simpleton ...1377
• GOM a foolish, awkward person; a simpleton; an idiot ...1996 Ireland
• GOMF a buffoon, a fool; an empty-headed fellow who makes a great deal of noisy mirth; a fool, or one who wishes to seem so ...1825 Sc.
• GONEY a stupid, awkward person; a foolish fellow; a simpleton ...1838 Amer. dial.
• GONK a fool; an idiot ...2003 UK teen sl.
• GONNER-HEAD a fool; a stupid fellow, a dunce ...1740 Eng. dial.
• GONNER-PATE a fool; a stupid fellow; a dunce ...Bk1900 Eng. dial.
• GONUS a fool, a dolt, a stupid fellow, an ignoramus, a simpleton ...1842 Amer. dial.
• GONY a stupid, awkward person; a foolish fellow; a simpleton ...1859 Amer. dial.
• GONZO a foolish person ...1977 sl., orig. & chiefly US
• GOOBER an idiot, a fool; an incompetent, a country bumpkin ...M19 sl.
• GOOBY a stupid, foolish person; a blockhead, a simpleton, a fool, a lout ...1790 Eng. dial.
• GOOF an oaf, a ridiculous jerk; an incompetent fool ...1916 US sl. & colloq.
• GOOF-BALL a jerk; an oaf; an incompetent fool ...1944 US sl.
• GOOFER an oaf, a ridiculous jerk; an incompetent fool ...20C US sl. & colloq.
• GOOFIE a fool ...1920s US campus sl.
• GOOFUS an oaf, a ridiculous jerk; an incompetent fool ...1917 US sl. & colloq.
• GOOFY a fool ...1920s US campus sl.
• GOOG a fool ...1910s sl.
• GOOGIE, GOOGY a fool ...1910s sl.
• GOO-GOO a silly fool ...1910s US sl.
• GOOK a dull, stupid, foolish person ...1910s sl., orig. US
• GOON a stupid, awkward person; a foolish fellow; a simpleton ...1921 sl., orig. US
• GOONEY a foolish or stupid fellow; a simpleton ...1815 Eng. & Amer. dial.
• GOONUS a fool, a dolt, a stupid fellow, an ignoramus, a simpleton ...1959 Amer. dial.
• GOONY a stupid, awkward person; a foolish fellow; a simpleton ...1948 Amer. dial.
• GOOP a foolish person ...1900 sl., orig. US
• GOOSECAP † a silly fellow; a stupid, foolish person; a simpleton; an idiot; a giddy or flighty young girl ...1589 obs. exc. Eng. dial.
​• GOOSTRUMNOODLE a stupid person; a fool ...1871 Eng. dial.
• GORBY a stupid, foolish person; a blockhead, a simpleton, a fool, a lout ...1790 Eng. dial.
• GORM a foolish person ...1912 sl.
• GOUK a dull, stupid, foolish person ...1910s sl., orig. US
• GOZZARD a fool, a simpleton ...B1900 Eng. dial.
• GRAMPUS a blusterer; a blustering fool ...1823 US sl., esp. nautical usage
• GREENLANDER a fool; a soft-head ...Bk1891 sl.
• GRIZZLEDEMUNDY a term of abuse applied to a person who laughs at any trifling thing; a grinning fool; a stupid oaf ...1818 Eng. dial.
• GROLL † a foolish or superficial person; a gossip, a smatterer ...1637
• GUBBINS a foolish person ...1916 Brit. sl.
• GUCK † a foolish saying; a fool ...1596 Sc.
• GULL-FINCH † a fool, a simpleton; a person easily deceived ...1630
• GULPIN one who will swallow anything; one easily gulled; a credulous simpleton; a fool ...1802
• GUMP a foolish person ...1722 sl., now US
• GUMPH a foolish person ...1722 sl., now US
• GUMP-HEAD a stupid, foolish, or awkward person; an idiot; a senseless person; a dolt ...1916 Amer. dial.
• GUMPUS a foolish person; a dolt ...1825 Sc.
• GUMPY a stupid, foolish, or awkward person; an idiot; a senseless person; a dolt ...1892 Amer. dial.
• GUM-SUCKER a fool, a simpleton ...1936 Aust.
• GUP a fool ...c1925 Aust. sl.
• GUPPY a fool ...c1925 Aust. sl.
• GUY a person who is an object of ridicule or derision; broadly, a fool ...1823 Amer. sl.
• HABERMAGULLION a fool; a useless person ...Bk1997 Ulster sl. 
• HAIR-BRAIN † one who has a brain like a hare’s, or no more brain than a hare; a giddy or reckless person; an oaf; a fool ...1550
• HAIRPIN a fool, a simpleton ...1876 US sl.
• HAIVERALL, HAIVEREL, HAIVREL a person given to foolish or inconsequential chatter or gossip; also, a stupid or ignorant person, a fool, a simpleton ...1772 Sc.
• HAL a fool, a jester; a silly person ...1857 Eng. dial.
• HALF-BAKE a fool, an inadequate person ...1943 UK sl.
• HALF-BAKED a half-baked person; a foolish, silly, or half-witted person; an immature person ...1866 colloq. & Eng. dial.
• HALF-CHAR a foolish fellow ...Bk1905 Eng. dial.
• HALF-IDIOT a complete fool ...1990 W. Indies sl.
• HALFLIN(G) a half-witted person; a fool ...1808 Sc. & Eng. dial.
• HALF-NATURAL a fool ...Bk1880 Eng. dial.
• HALF-ROCK a foolish or half-witted fellow ...1893 Eng. dial.
• HALF-THICK a foolish fellow ...1896 Eng. dial.
• HALF-WIT a foolish person ...1755 sl. 
• HALFY a fool; a half-witted person ...Bk1905 Eng. dial.
• HALIBUT a foolish or offensive person ...1905 US sl.
• HALLACKING a foolish person ...1841 Eng. dial.
• HALLIKIN a foolish person ...Bk1877 Eng. dial.
• HALLOCKIT a noisy, restless person; a romp, a hoyden; a fool, a good-for-nothing, a worthless person ...1787 Sc.
• HAMBURGERHEAD a stupid or worthless person; a fool; one who has no more brains than a hamburger ...1955 US sl.
• HAMHEAD a fool, a stupid or worthless person ...1927 US sl.
• HAMPTON (WICK) a fool ...1989 UK rhyming sl. for 'prick'
• HANDLE a fool ...1835 UK sl.
• HANKTELO a silly fellow; a fool; a simpleton ...1593 UK sl.
• HANS WURST a fool, an idiot ...1869 US sl.
• HA'P'ORTH a 'halfpennyworth'; a fool ...1974 UK sl.
• HARDHEAD an unthinking or unintelligent person; a blockhead; a fool; a stupid person; also, a person who is stubborn and uncompromising ...1576
• HARE-BRAIN † one who has a brain like a hare's, or no more brain than a hare; a giddy, reckless or rash person; an oaf, a fool ...1550
• HARRY HUGGINS a fool, an idiot ...1992 UK rhyming sl. for 'muggins'
• HASH one who talks nonsense; a fool; a scamp; also, a term of endearment for a boy ...1685 Sc. & Eng. dial.
• HAUM-GOBBARD a silly, clownish fellow; a foolish person ...1790 Eng. dial. 
• HAVERAL-HASH a silly, nonsensical person; a fool ...1870 Sc.
• HAVEREL, HAVERIL, HAVREL a foolishly chattering or garrulous person; one given to inconsequential chatter or gossip; a fool; a stupid, half-witted, or ignorant person; a simpleton ...1772 Sc. 
• HAWBUCK an ungainly or clumsy person; an unmannerly lout; a country bumpkin or clown; a rude, ignorant rustic; a coarse, vulgar lad; a foolish or stupid fellow; a simpleton; a noisy, rough, turbulent young man ...1787
• HAWFLIN a half-witted person; a fool ...1808 Sc. & Eng. dial.
• HAWG a 'hog'; a miser, a mean person; a foolish person ...1940 US sl.
• HAZE-BAZE a fool, a stupid person, a ninny ...1877 Ireland
• HEAD JOB a fool ...2003 NZ sl.
• HEAD-THE-BALL a foolish or silly person; an idiot; also, a crazy person, esp. one who is violent or unpredictable ...1958 colloq., chiefly Irish & Sc.
• HEARTH-RUG a fool; a simpleton ...1998 Brit. rhyming sl. for 'mug'
• HEATHER-GOOSE a dolt, a fool, a ninny ...c1870 Sc.
• HEEPY † a fool, a stupid person ...1800 Sc.
• HELIUM-BRAIN a silly or empty-headed person; a fool; an airhead ...1978 US college sl.
• HELIUM HEAD a silly or empty-headed person; a fool; an airhead ...1960 US college sl.
• HELLICAT * a bad, worthless, or foolish person; a wicked or cruel person; a villain ...1816 orig. & chiefly Sc.
• HERBERT a stupid, foolish, ridiculous, or inconsequential person ...1960 Brit. sl.
• HERKIMER JERKIMER a rustic, a fool, a screwball ...1946 Amer. sl.
• HERRING a worthless, foolish, offensive, or inconsequential person ...1575 sl.
• HICHCOCK † a term of contempt; a simpleton; a fool ...1607
• HICK JOP a country bumpkin; a fool ...1809 sl.
• HOBALL † a clown, a fool, a dolt, an idiot ...a1553
• HOBBIL, HOBBLE a fool, a dull, stupid person; a blockhead, a dunce, an idiot ...1740 Sc. & Eng. dial.
• HOBBY HORSE a fool, a jester ...L16 sl.
• HOB-GOB a fool, an idiot; an awkward, uncouth person ...B1900 Eng. dial.
• HODDY-DODDY † a foolish or ridiculous person; a simpleton; a dupe ...1646
• HODDY-NODDY †* a fool, simpleton, noodle ...1600
• HODDYPEAK † a fool, a simpleton, a blockhead ...1500
• HORSE MARINE a lubberly or clumsy fool; a dolt ...1823 US nautical & military usage
• HORSE'S ASS a fool ...Bk1995 US sl.
• ICK a fool, a gullible or easily deceived person ...1930s US Black sl.
• ICKAROO a fool, a gullible or easily deceived person ...1930s US Black sl.
• IDIOT a term of reprobation for one who speaks or acts in what the speaker considers an irrational way, or with extreme stupidity or folly; a blockhead; a stupid person; an utter fool; a crazy person ...c1375
• IDYAT BWAI a fool ...1997 W. Indian patois (idiot boy) 
• IG MAN an ignorant man; a fool ...20C US Black sl.
• IGNARO † one that is ignorant; a fool, a blockhead, a dunce, an ignoramus ...1620
• IGNO a fool ...1970s US sl.
• IGNUTS an ignorant fool ...1934 US sl.
• IMBO a simpleton, a fool; an imbecile; a gullible person, esp. the victim of a criminal ...1953 Aust. sl.
• IMBY a fool, a simpleton ...1980s US sl. 
• IMPLEMENT a fool easily engaged in any enterprise, though difficult or dangerous ...1690 sl.
• INCOMPOOT a nincompoop, a fool, a silly person, a trifler ...Bk1902 Eng. dial.
• INSIPIENT † an unwise, foolish or silly person ...1494
• IRONHEAD a stupid oaf, a fool ...20C sl.
• ISRAEL a fool, an idiot ...Bk1902 Eng. dial.
• IT-SHAY an oaf or a fool ...20C US Pig Latin for 'shit'
• IVORY DOME a stupid person; a fool ...1911 US sl.
• J a fool, an oaf ...19C Brit. sl.
• JACK a fool ...1548
• JACK-ADAMS a foolish and stubborn person; a simpleton; a silly, impertinent fellow ...1690 sl.
• JACKALALLY a foolish person ...Bk1893 Eng. dial.
• JACK AND JILL. a fool ...1973 Aust. rhyming sl. for 'dill'
• JACK-A-NODS a simple, stupid fellow; a fool; a simpleton...Bk1852 Eng. dial. 
• JACKASS a foolish or stupid person; an idiot, a dolt ...1756
• JACK-FOOL a great fool ...1383 sl.
• JACK LANTERN a fool; a dull, stupid fellow ...1896 Amer. dial.
• JACOB † a simpleton; a fool; a half-witted fellow; an oaf ...1785 sl.
• JARHEAD (derogatory) a dull, stupid person; a fool, an oaf ...1969 Amer. dial.
• JAZZBO a clumsy, clownish or foolish person; an oaf; a rude or annoying person ...1923 Amer. sl.
• JEEP a foolish, inexperienced, or offensive individual ...1938 Amer. sl.
• JENNYASS a female fool ...1940 Amer. dial.
• JERK an oaf or incompetent fool ...1935 US sl.
• JIMCRACK a fool, an idiot, a half-witted person ...1908 Amer. dial.
• JOBARD † a stupid fellow; a fool ...a1400
• JOBBERNOWL a stupid, thick-headed person; a blockhead, a fool, a dunce, a dolt ...1592 colloq.
• JOE ERK a fool; an oaf; a jerk; a wretched man ...World Wars rhyming sl. for 'jerk' and 'berk'
• JOE HUNT a fool; an oaf; a jerk; a wretched man ...20C Brit. rhyming sl. for 'cunt'
• JOLTERHEAD a fool; a stupid person ...L18 sl.
• JOLTHEAD a fool; a stupid person ...L18 sl.
• JUGGINS a dolt; a fool; a soft-head; gullible person; a dupe ...1682
• KANG † a fool ...a1225
• KIME †* a simpleton, a fool, a silly fellow...c1305
• KLUCK a stupid oaf; a fool ...20C US colloq.
• KNOCK-SOFTLY a silly or stupid person; a fool ...1887 Eng. dial.
• KNOW-NOTHING one who knows nothing; an ignorant person; a fool ...1839
• LABBET a fool ...Bk1902 Eng. dial.
• LABRICK a fool; a dolt; an idiot; a dull, stupid person; a greenhorn; a stranger; a naive or foolish person; often used as a mild term of abuse ...1889 Amer. sl.
• LACK-BRAIN one who is destitute of sense or brains; one wanting in wit; a stupid, empty-headed fellow, a fool ...1596
• LALDRUM a simpleton; a complete fool ...Bk1902 Eng. dial.
• LAMB a simpleton, a fool, esp. one easily cheated of their money ...1668
• LAME a person who is 'lame'; a fool, an idiot; an unsophisticated person; one who does not fir in with a particular social group  ...1958 US sl., chiefly Black usage
• LAMEBRAIN a fool, an idiot ...1919 US sl.
• LAME-O a fool; an idiot; an unsophisticated person ...1977 US college sl.
• LAMER a person who is 'lame'; a fool, an idiot; an unsophisticated person ...1961 US sl.
• LAMESTER a foolish or contemptible person ...1978 US sl.
• LANE a person easily imposed upon or cheated; a victim; also, one who is foolish or socially unsophisticated ...1933 US sl., esp. Black & criminals' usage
• LARRY a fool ...20C Irish sl.
• LAVERICK a fool; a dolt; an idiot; a dull, stupid person; a greenhorn; a naive person; a stranger; often used as a mild term of abuse ...1895 Amer. dial.
• LEATHER-EARS a stupid person; a fool; one slow of comprehension ...1903 Amer. dial.
• LEATHER-HEAD a fool, a blockhead, a dolt, an oaf, a stupid person; a person slow of comprehension ...a1700
• LEATHER-NECK a stupid person; a fool; a blockhead; an uncouth person ...1919 Amer. dial.
• LEMON a victim; a fool ...1908 sl.
• LIGHTS a fool; a soft-head; an oaf ...1682 Brit. colloq.
• LINTBRAIN a foolish, dim-witted, or ignorant person ...1990 US sl.
• LINTHEAD a foolish, dim-witted, or ignorant person ...1960 US sl.
• LOB-COAT † a country bumpkin; a clown, a lout, a boor; a heavy, dull person; a blundering fool ...1604
• LOBCOCK † a country bumpkin; a clown, a lout, a boor; a dull, stupid, sluggish person; a clumsy, lubberly fellow; a blundering fool; a blockhead; a term of abuse ...a1553 obs. exc. Eng. dial.
• LOGGERHEAD a fool; a dullard ...L16 sl.
• LOMMIX a large, heavy, or clumsy person; an ungainly or stupid lout; a fool ...M19 sl.
• LOOB a fool, a dullard ...M14 Eng. dial.
• LOOBY a fool; a soft-head ...Bk1891 sl.
• LOOGAN a foolish person ...1929 US sl.
• LOONY a fool; a soft-head ...Bk1891 sl.
• LOOP a fool ...1940s Aust. sl.
• LOX a fool; a lummox ...1966 Amer. sl.
• LOX-FOR-BRAINS a fool ...1977 Amer. sl.
• LUB a fool ...M14 sl.
• LUBBER a fool; a soft-head ...M14 sl.
• LUMMIX, LUMMOCK(S), LUMMOX, LUMMUX a large, heavy, or clumsy person; an ungainly or stupid lout; a fool ...M19 sl.
• LUMMOKIN a large, heavy, or clumsy person; an ungainly or stupid lout; a fool ...M19 sl.
• LUNATIC a madly foolish person ...1602
• LUNCH a dull, stupid person; a fool ...1960s US college sl.
• LUNCHBAG a dull, foolish person; an undesirable person ...1950s US college sl.
• LUNCHBOX a dull, foolish person; an undesirable person ...1950s US college sl.
• LUNCHBUCKET a dull, foolish person; an undesirable person ...1950s US college sl.
• LUNCHIE a dull, stupid person; a fool ...1960s US college sl.
• LUNCHPAIL a dull, foolish person; an undesirable person ...1950s US college sl.
• LUNCHSACK a dull, foolish person; an undesirable person ...1950s US college sl.
• LUNK a fool ...M19 US sl.
• LUNKHEAD an absolute fool; an idiot; an incompetent ...M19 sl., orig. US
• LUSH a victim or fool ...1940s US sl.
• MACARONI a merry fool, esp. if an Italian ...1711 colloq.
• MACAROON † a buffoon; a stupid or foolish person; an affected blockhead; a ridiculous or doltish person ...a1631 
• MACKEREL (AND SPRAT) a worthless, stupid or foolish fellow ...1863 Brit. rhyming sl. for 'prat'
• MACKY-MOON a fool, a silly person; one who makes himself absurd or ridiculous by playing the fool; a queer-looking figure ...1872 Eng. dial.
• MACO a fool, an idiot ...20C W. Indies sl.
• MADDLIN(G) a fool, simpleton, blockhead ...Bk1905 Eng. dial.
• MAD HADDOCK a very eccentric, crazy, or foolish person ...20C Aust. sl.
• MADLING a mad creature; one who acts wildly or foolishly ...c1648-50
• MADPASH † a foolish or insane person; a lunatic, a mad fellow; a crackbrained person; a scatterbrain; a hot-headed person; a rash or turbulent person; a wild, giddy person ...1611 
​• MAFF a fool; a foolish, silly person ...Bk1905 Eng, dial.
• MAFFLARD † a stammering or blundering fool; a term of contempt ...c1450
• MAFFLIN a simpleton; a silly, foolish person ...Bk1905 Eng, dial.
• MAGHNOON a fool; a dolt; an idiot ...L19 among troops in Egypt
• MAGOO a useless or foolish person; an absent-minded or inattentive person ...1932 Amer. sl.
• MAGUFFIN a foolish, blundering person, an oaf ...1832 Sc.
• MAISLIN a fool, a simpleton, an idiot ...1781 Eng. dial.
• MAISLYKIN a fool, a simpleton, an idiot ...1781 Eng. dial.
• MAKIN a fool, a simpleton ...Bk1905 Eng. dial.
• MAKO a fool, an idiot ...20C W. Indies sl.
• MALLETHEAD a fool, a stupid person, a numbskull ...1954 US sl.
• MAMELT, MAMMELT a simpleton, a fool ...1790 Eng. dial.
• MAMMY-GOG a foolish, stupid person ...1884 Eng. dial.
• MAMMY-SUCK a foolish, stupid person ...Bk1905 Eng. dial.
• MAN IN THE MOON a fool, an eccentric or crazy person ...20C rhyming sl. for 'loon'
• MANMANPOUL a gullible fool ...20C W. Indies sl.
• MARLOCK one who plays pranks; a fool ...1790 Eng. dial.
• MAROON an obnoxious or foolish person; a stupid person  ...1941 Amer. sl.
• MATHUM a fool, a stupid person; a blockhead ...Bk1905 Eng. dial.
• MAWKS a foolish, slatternly woman; an overgrown, clumsy girl ...1721 Eng. dial.
• MAY-GAME a foolish, silly person ...1886 Eng. dial.
• MAZED-ANTIC a wild, foolish, crazy person ...Bk1905 Eng. dial.
• MAZICAN a stupid person; a fool ...Bk1905 Eng. dial.
• MAZLEKIN a fool, a simpleton, an idiot ...1781 Eng. dial.
• MAZLIN a fool, a simpleton, an idiot ...1781 Eng. dial.
• MAZY-JACK a fool, an idiot; a parish fool ...1876 Eng. dial.
• MCFLY a fool; an empty-headed person ...1980s US campus sl.
• MEATHUM a fool, a stupid person; a blockhead ...Bk1905 Eng. dial.
• MEE-MAW a simpleton, a fool ...1895 Eng. dial.
• MENTAL GIANT a fool, an idiot ...1980s US campus sl.
• MENTAL HERNIA a fool; an idiot; an oaf; a stupid person ...1970 Amer. sl.
• MESS an objectionable or foolish person; unruly or incorrigible person; an oaf; a hopelessly stupid person; a mentally confused person ...1936 sl.
• MICKEY MOUSE a small, timid, inconsequential, or foolish person ...1941 
• MOAK, MOKE a stupid fellow, a dolt, a blockhead; a foolish or inconsequential fellow ...1855 Eng. dial. & sl.
• MOBARD, MOBBARD †* a villain, a rascal; a fool; a clown, a boor ...a1450
• MOBY DICK a fool, an idiot ...Bk2004 Brit. rhyming sl. for 'prick'
• MOEGIE, MOEGOE, MOGGOE, MOGO - (derogatory) a country bumpkin; a rustic; a dull, foolish, or gullible person; a person who fails to fit in, a misfit; a lazy lout ...1953 S. Afr. colloq.
• MOISEY, MOISY - a person of soft intellect, an idiot, a fool ...Bk1905 Eng. dial.
• MOKE a person who is stupid, awkward, or incompetent; a dolt, a fool ...1855 colloq.
• MOKES a foolish or inconsequential fellow; a stupid fellow ...1985 Amer. sl.
• MOLLY a fool ...1905 US sl.
• MOLLY-BOOBY a foolish person ...1965 Barbados sl.
• MOLLYHAWK a fool, a simpleton, an idiot ...1900 sl.
• MOLLYHEAD * a fool; a simpleton; an idiot  ...1902 sl.
• MOME †* a fool, a stupid or silly person; a blockhead, a simpleton; a dull, ignorant person; a dolt ...1550
• MOMPARA an incompetent person; a fool; an idiot; also used affectionately, and as a form of address ...1930 S. Afr. colloq.
• MONAGHAN † a clown, a fool ...1689 Ireland colloq.
• MONG (offensive) an idiot; a fool; a mentally slow or backward person ...1980 Brit. colloq.
• MONGY (offensive) an idiot; a fool; a mentally slow or backward person ...2000 Brit. colloq.
• MONIMENT a ridiculous or objectionable person; a laughingstock, a fool, a rogue ...1866 Sc.
• MONKEY a child; a junior; a foolish person ...1583
• MONUMENT a ridiculous or objectionable person; a laughingstock, a fool, a rogue ...1866 Sc.
• MOO (humorous or derogatory) a person regarded as misguided, foolish, or incompetent, usually a woman ...Bk1909
• MOOFUS a fool ...1920 US sl.
• MOOJIN a fool, a simpleton ...1996 W. Indies
• MOOK (derogatory) a term of abuse; an incompetent, ineffectual, foolish, or stupid person; a contemptible person (esp. with reference to low social status) ...1930 US & Caribbean colloq.
• MOO-MOO a fool, a simpleton ...1973 W. Indies sl.
• MOONCALF a born fool; a congenital idiot; a simpleton ...1627 colloq.
• MOONEY a fool; a soft-head ...Bk1891 sl.
• MOON-HEAD a silly, awkward fellow; an oaf; a fool ...1919 Amer. dial. 
• MOONLING † * a simpleton, a fool, an idiot, a silly fellow, a lunatic ...1631
• MOONRAKER a very foolish or silly person; a blockhead ...c1840 Brit. colloq.
• MOONY a fool; a silly fellow; a simpleton; a soft-head ...1682 sl.
• MOOSIE, MOOSY, MOOZY a person of soft intellect, an idiot, a fool, a blockhead, a stupid person ...Bk1905 Eng. dial.
• MOP † a fool, a simpleton, an oaf ...c1330
• MOPE a fool, a stupid person, a simpleton; a dolt, an oaf; a dullard; a slow-witted or inept person ...c1390
• MOPEY a fool; used as a term of derogatory address ...1920s sl.
• MOPOKE a stupid, ineffectual, or tiresome person; a slow or lugubrious person; a fool; often used as a term of abuse ...1845 chiefly Aust.
• MOP-STICK †* a stupid person; a fool; an idiot ...1882 sl.
• MORBAN a silly, foolish person ...Bk1879 Eng. dial.
• MOREPORK a stupid or tiresome person; a fool; often used as a term of abuse ...1845 Aust. colloq.
• MOREPORK KIND OF A FELLOW a stupid or tiresome person; a fool ...1845 Aust. colloq.
• MOROLOGIST †* a person who talks foolishly; a prating, foolish fellow ...1727
• MORON a stupid or slow-witted person; a fool; an idiot; a feeble-minded person; a dunce ...1917 colloq., orig. US
• MOROSOPH * a wise fool, a jester ...1693
• MOS(E)Y - a person of soft intellect; an idiot, a fool ...1824 Sc.& Eng. dial. 
• MOTHBALL * an insignificant or foolish person; an obnoxious or aggravating person; a teenage jerk; an irritating person; an over-diligent student ...1944 US sl.
• MOTLEY † a fool, a jester in motley garments...a1605
• MOTLEY FOOL a professional fool ...a1616
• MOTORHEAD a fool ...1973 US sl.
• MOUSEBRAIN a fool, a birdbrain ...1914 Amer. sl.
• MOUTH a person who talks foolishly; a slow-witted or gullible person; a fool; a dupe ...1663 orig. cant
• MOUTH-BREATHER a stupid person; a fool ...1915 Amer. sl.
• MOUZY a person of soft intellect, an idiot, a fool ...Bk1905 Eng. dial.
• MOZEY, MOZIE, MOZY a person of soft intellect; an idiot, a fool ...1824 Eng. dial.
• MR. NAWPOST a foolish fellow ...c1696 sl.
• MUD a fool; an oaf; a stupid person ...18C Brit. colloq.
• MUDDING-FACE a fool; a weakling ...L19 sl.
• MUDDLE-HEAD a fool; a simpleton; a stupid person; an oaf  ...M19
• MUD-HEAD an oaf; a fool; a stupid person ...E19 colloq.
• MUFF an oaf, a fool, a stupid person ...1682 cant
• MUFFIN a fool ...1830 Brit. sl.
• MUFFIN-CAP a fool ...M19 sl.
• MUG a stupid or incompetent person; a fool or simpleton; a gullible person, a dupe ...1857 colloq.
• MUGGINS a foolish person ...1855 sl.
• MUGGY-CUNT a fool ...2000 UK sl.
• MUG LAIR a showy but foolish person ...1944 Aust. sl.
• MULLETHEAD a fool, a stupid person ...1857 US sl.
• MULLOCK (derogatory) a worthless or foolish person ...1890 Aust. & NZ sl.
• MUMMYDIDDLE a stupid, silly person; a foolish person ...Bk1903 Eng. dial.
• MUMMYHEAD a fool ...1990s US Black gang usage
• MUSH a fool ...20C US sl.
• MUSH-FACE a fool; a sentimental idiot ...1920s sl.
• MUTANT a clumsy, foolish, or otherwise unpopular individual; generally used by adolescents ...sl.
• NABALL a fool ...1612 sl.
• NAF a fool; a weakling; an ineffectual person ...1960s S. Afr. sl.
• NAILHEAD a dull, stupid person; a fool ...1948 Amer. sl.
• NANA a foolish person ...1941 sl., orig. Aust.
• NANNICOCK †* a silly, affected person; a young woman, as a term of contempt; also, a fool ...1600
• NANNY-CRATTY an inquisitive, meddlesome, foolish, weak-minded person ...Bk1905 Eng. dial.
• NANNY-GOAT a foolish girl or woman ...1900 Eng. dial.
• NANNY-HAMMER a foolish person ...1881 Eng. dial.
• NARNA a fool, an idiot, an incompetent ...1960s sl.
• NATURAL FOOL one who is by nature deficient in intelligence; a fool or simpleton by birth ...c1430
• NATURAL IDIOT † one who is by nature deficient in intelligence; a fool or simpleton by birth ...1540
• NAUMPEY a weak, foolish-minded person ...Bk1905 Eng. dial.
• NAZOLD a silly or weak-minded person; a vain fool ...1607 colloq.
• NAZZARD an insignificant or feeble person; a worthless scamp; a silly, foolish fellow ...1619 obs. exc. Eng. dial.
• NEDDY a fool, a simpleton ...1793 Sc. & Eng. dial.
• NENA a fool, an idiot, a ninny ...1870 Eng. dial.
• NERK a fool; a generally unacceptable person ...1950s sl.
• NERVOUS NELLIE, NERVOUS NELLY a fearful, foolish, and timid person ...1920s US sl.
• NIB a fool ...Bk1902 printers' sl.
• NICKIN a fool, a simpleton ...L17 sl.
• NICK-NINNY † a simpleton, an empty fellow, a fool ...c1696 sl. or Eng. dial.
• NICKUMPOOP a fool; an oaf; a jerk ...L17 sl.
• NIDDICOCK †* a fool, a simpleton, a ninny ...1586
• NIDDIPOL a fool ...1583 sl.
• NIDDLETY-NOD a foolish person ...B1900 Eng. dial.
• NIDDY-NODDY a fool, idiot, or simpleton ...1889 Eng. dial.
• NIGGET † a fool, simpleton, idiot ...B1900
• NIG-NOG a foolish person ...1953 Brit. sl.
• NIKEY a fool, a simpleton ...L17 sl.
• NIKIN a fool, a simpleton ...L17 sl.
• NIMSHI, NIMSHY a conceited fellow; a foolish fellow; a nincompoop; one who habitually acts in a foolish manner; a mischievous child  ...1848 Amer. dial.
• NINCOMPOOP a foolish person ...1676
• NING-NANG a worthless or troublesome person; an unreliable person; a silly or stupid person; a fool ...1832 Eng. dial.
• NINGNONG a fool, an idiot, a stupid person ...1832
• NINKOMPOOP a fool; an oaf; a jerk ...L17 sl.
• NINNY a fool; an oaf; a simpleton ...1533
• NINNYHAMMER a stupid or weak-minded person; a simpleton, a fool ...1592
• NINNY-NONNY a silly, weak-minded, or foolish person ...1823 Eng. dial.
​• NINNY-WHOOP †* a fool, a simpleton, a ninny ...1653
• NISEY † a fool; a silly fellow; a simpleton; a dunce ...c1684-6
• NIT a nitwit; an oaf; a fool ...1588 colloq.
• NITWIT a simpleton, a moron, a fool ...1914 US sl.
• NIZY a fool; a dunce ...L17 sl.
• NIZZIE a fool; a dunce; a soft-head ...L17 sl.
• NOCKY † a silly, dull fellow; a foolish person; a simpleton, a dullard; an oaf ...a1700 obs. rare exc. Eng. dial.
• NOCKY BOY a dull oaf; a fool ...17C colloq.
• NODCOCK a simpleton; a fool; an oaf ...M16
• NODDIPOL an oaf; a fool ...16C colloq.        
• NODDY an oaf; a fool; a simpleton ...16C colloq.
• NODDY-HEAD an oaf; a fool; a simpleton ...16C colloq.
• NODDY-PATE a simpleton, an idiot, a fool, an oaf ...1660
• NODDY-PEAK(E) an oaf; a fool; a simpleton ...16C colloq.
• NODDY-POLE an oaf; a fool; a simpleton ...16C colloq.
• NODDY-POLL an oaf; a fool; a simpleton ...16C colloq.
• NODGECOCK a simpleton; a fool; an oaf ...M16
• NOGGY a young fool, a blockhead ...B1900 Eng. dial.
• NOKES †* a fool, a simpleton, a ninny ...a1700
• NONG an oaf; a dolt; a stupid person; a fool; an idiot ...1944 Aust. sl.
• NONG-NONG a foolish person ...1944 Aust. sl.
• NOODLE a foolish person ...1753 sl.
• NULLY a foolish person ...1973 sl.
• NUMB CREATURE a fool, a stupid person ...1941 Amer. dial.
• NUMBHEAD a fool, a stupid person ...1941 Amer. dial.
• NUMB NUT a fool, a stupid person ...1966 sl.
• NUMBSKULL, NUMSKULL a fool; a blockhead; a dull-witted person; a dunce; a dolt; a stupid fellow ...1742
• NUMBY a fool, a stupid person ...1966 Amer. dial.
• NUM-CUMPUS one who is non compos mentis, or not of sound mind; a fool ...1882 Eng. dial.
• NUMP a dolt; an oaf; a silly or stupid person; a fool; a blockhead ...17C Brit.
• NUMPS † a silly or stupid person; a fool, a blockhead, a dolt ...1611 obs. exc. Eng. dial.
• NUMPTY a fool; an idiot ...Brit. sl.
• NUMPY a fool, a dolt ...1941 Amer. dial.
• NUPSON † a simpleton, a fool ...1607
​• NUT a crazy or insane person; an eccentric; a foolish person ...1908 sl.
• NUTHATCH a madman; a fool ...1972 Amer. sl.
• NUTHOUSE a fool ...1926 Amer. sl.
• OAF a half-wit; a simpleton; a fool; a stupid fellow; a blockhead; an idiot; a dolt; an awkward, blundering lout; the clown of a circus ...1638
• OAFO an oaf; a socially inferior fool; a lout ...1959 UK sl.
• OANSHACH a foolish person, an idiot ...1950 Sc.
• OANSHAGH a female fool ...Bk1910 Ireland 
• OASHACH a foolish person, an idiot ...1950 Sc.
• OHMADAUN a fool ...M19 Ireland
• OINSEACH a female fool ...2001 Irish sl.
• OLD BAT a disagreeable, middle-aged or elderly woman; an unpleasant or despicable female; an unattractive or foolish old woman ...1886 UK sl.
• OLD BUFFER a foolish old person ...1749 Brit. sl.
• OLD COOT a foolish or cantankerous old person; also used affectionately ...M18 sl.
• OLD FART a fool, an unpleasant person, older than the speaker ...M18 sl.
• OMADAUN a stupid person; a simpleton, a fool; a lazy, good-for-nothing fellow ...1843 Ireland
• OMADAWN a fool ...M19 Ireland
• OMADHAUN a fool, a simpleton; a dull, stupid person; a term of abuse ...1818 Ireland
• ONE a fool, a dupe ...1980s sl.
• OOK a jerk, a fool, a stupid person ...1949 Amer. sl. 
• OONCHOOK a foolish person ...1937 Irish & Can.
• OONSHI(C)K a fool or simpleton; a clot...1825 Irish & Newfoundland sl. 
• OONSHUGH a foolish woman ...Bk1905 Ireland
• OYSTER an odd, stupid, or foolish person ...1930s US sl.
• PAEPS a foolish youth ...Bk1869 Eng. dial.
• PAISAN a fool ...1950 Amer. dial.
• PAISANO a fool ...1950s sl.
• PAMPOEN a fool ...1940s S. Afr. sl.
• PANHANDLE a fool; an unpleasant person ...1990s sl.
• PANTALOON † a term of contempt applied to an enfeebled, tottering old man; a dotard, an old fool ...1596-1600
• PANWIT a fool ...1990s UK juvenile sl.
• PAPER HAT a fool ...1960s rhyming sl. for 'prat'
• PAPER SCULL a fool ...L17 sl.
• PAPER SKULL a fool ...L17 sl.
• PAPES a foolish youth ...Bk1905 Eng. dial.
• PAPPYSHOW a fool, or someone who presents the appearance of a fool; one who makes a stupid exhibition of themselves ...1940 Trinidad and Tobago
• PASTIE a fool; used as a friendly term of abuse ...2004 UK sl.
• PATTIC(K) a fool, simpleton, a silly person; one who talks nonsense; a merry fellow ...1856 Eng. dial.
• PEA-BRAIN (derogatory) a foolish or unintelligent person ...1938 colloq.
• PIE EATER * (derogatory) a contemptible person; a fool; a country bumpkin; also, a person who accepts political favours ...a1891 US sl.
• PIE-FACE a foolish person ...1922 US sl.
• PIGEON a fool; a soft-head ...Bk1891 sl.
• PIG-SCONCE a pig-headed fellow, a blockhead, a fool, a dullard ...1631
• PILLOCK a foolish man ...1967 Brit. sl.
• PISS-HEAD an oaf; a fool; a jerk ...20C US sl.
• PLONKER a foolish person ...1966 Brit. sl.
• POGGLE † a crazy or foolish person; an idiot ...E19 Indian now rare or obs.
• POON (derogatory) a simple or foolish person ...1940 Aust. sl.
• POOP a foolish person ...1915 sl.
• POPPY SHOW foolishness, showing off; one who makes a stupid exhibition of themselves ...L19 W. Indies
• PORK a fool ...1970s sl.
• POSSUM * a fool, a simpleton, a gull ...1945 Aust. sl.
• POTATOHEAD a fool, a simpleton, a stupid person, a dunce, an oaf ...1952 Amer. sl.
• POTHEAD a fool; a blockhead; a stupid person ...1825 sl.
• POTTY a fool ...1950 UK sl.
• POTTY-CLOCK a foolish person ...Bk1862 Eng. dial.
• POT-WALLOPER (derogatory) a fool, a stupid person; also, an impostor, an upstart ...1820
• PRAT a foolish person ...1968 Brit. sl.
• PRAWN a person likened to a prawn in appearance or character, esp. in being foolish or foolish-looking ...1845
• PRIZE PACKAGE a fool ...1920s US sl.
• PRONK a foolish person ...1959 sl.
• PROPER CHARLIE, A a foolish person ...1946 sl., chiefly Brit.
• PROPER CHARLEY, A a complete fool ...c1960 sl.
• PUDDEN a fool ...Brit. sl.
• PUDDING a fool ...Brit. sl.
• PUGGLE a crazy or foolish person; an idiot ...E19 Indian now rare or obs.
• PUMBLECHOOK a stupid person; a fool; an oaf; a 'human ass' ...L19 Brit. & US sl.
• PUPPY SHOW foolishness, showing off; one who makes a stupid exhibition of themselves ...L19 W. Indies
• PUTTY-HEAD a fool; a stupid person ...1905 Amer. dial.
• PUTZ a foolish, clumsy, or unfortunate person ...1964 Amer. sl.  
• QUAD a very clumsy, stupid person; an inept fool ...1977 US college sl. 
• QUASHIBA a foolish, uncultivated woman ...1940s W. Indies sl.
• QUEER a fool, a simpleton ...1950s Aust. sl.
• QUEER CULL a foolish dandy, a fop ...L17 sl.
• QUILT a fool, someone who acts against their own interests ...20C Irish sl.
• QUIMMO a fool; an unpleasant person ...1999 UK sl.
• QUINCE a weakling; a fool ...20C Aust. & US sl.
• RAASHOLE a derogatory description of a person; a general term of abuse; a contemptible person; a great fool; an idiot ...1959 W. Indies & UK Black sl.
• RABBIT a simpleton; a fool; a silly person; a victim ...1900 Aust. sl.
• RADGEPOT an idiot; a fool ...1979 UK sl.
• RAFE a fool, a stupid person ...Bk1904 Eng. dial.
• RAFFLE-TOPPIN(G) a wild, reckless, foolish person ...19C Eng. dial.
• RAG a fool ...1960s sl.
• RAISIN-BRAIN a fool; a term of abuse ...1990s US Black sl.
• RALPH a fool; an oaf ...18C colloq.
• RALPH-SPOONER a fool ...L17 Eng. dial.
• RAWNY a silly fellow; a fool ...B1900 Eng. dial.
• RIGHT CHARLEY, A a complete fool ...c1960 sl.
• RIGHT CHARLIE, A a foolish person ...1946 sl., chiefly Brit.
• RIGHT NANA a fool, an idiot, an incompetent ...1960s sl.
• RODNEY a fool ...M19 Eng. dial. & colloq.
• RUMMY a foolish person; a weak-minded person ...1912 US sl.
• S.A.B. a Social Airhead Bitch ...1980s US college sl.
• SADDLE-GOOSE † a nickname for a fool ...1526
• SAINT-AGNES TÔTLE a stupid old fool ...Bk1904 Eng. dial.
• SAM a fool, a simpleton ...a1790 sl.
• SAM-DINGLE a term of contempt for a fool; a simpleton ...Bk1904 Eng. dial.
• SAMMY a simpleton, a fool; an ill-natured fellow; an effeminate weakling; a lunatic ...1876 Eng. dial.
• SAMMY BILLY a simpleton; a foolish, stupid person ...Bk1887 Eng. dial.
• SAMMY CODLIN a simpleton; a foolish, stupid person ...1889 Eng. dial.
• SAMMY DAWKIN a simpleton; a foolish, stupid person ...1879 Eng. dial.
• SAMMY DINGLE a simpleton; a foolish, stupid person ...Bk1887 Eng. dial.
• SAMMY-HEAD a simpleton; a foolish, stupid person ...Bk1904 Eng. dial.
• SAMMY NODDY a simpleton; a foolish, stupid person ...Bk1875 Eng. dial.
• SAMMY SOFT a fool; an oaf ...c1840 sl.
• SAMMY SUCK-EGG a simpleton; a foolish, stupid person ...Bk1896 Eng. dial.
• SAP a simpleton; a blockhead; a fool ...1817 Sc. & Eng. dial.
• SAPADILLO a simpleton; a blockhead; a fool; a dunce ...1817 sl.
• SAP-CRUST a fool; a blockhead ...1899 Sc.
• SAPEROO a gullible person; a dupe; a complete fool ...1950 Amer. sl. 
• SAP-HEAD a fool; a simpleton; a stupid person; a blockhead ...1798
• SAPOLIO a simpleton; a blockhead; a fool; a dunce; a dupe ...1817 sl.
• SAPOLO a simpleton; a blockhead; a fool; a dunce ...1817 sl.
• SAPP a simpleton; a blockhead; a fool; a dunce ...1817 sl.
• SAP-PATE † a fool, a simpleton ...a1700
• SAPPER a simpleton; a blockhead; a fool; a dunce; a dupe ...1817 sl.
• SAPPO a simpleton; a blockhead; a fool; a gullible person; a dunce; a dupe ...1817 sl.
• SAPPY a fool; a blockhead ...1868 Eng. dial.
• SAPPY-CRUST a blockhead, a fool ...Bk1904 Eng. dial.
• SAPPYHEAD a fool ...M19 sl.
• SAP-SCAUP a simpleton; a fool; a blockhead ...Bk1873 Eng. dial.
• SAPSCULL, SAPSKULL † a silly fellow, a fool, a blockhead, a simpleton ...1735 obs. exc. Eng. dial.
• SAP-TOPPIN a simpleton; a fool; a blockhead ...1876 Eng. dial.
• SARDINE a term of reproach or abuse; a fool; a simpleton; a stupid fellow; a dullard ...1857 US sl. 
• SART-AND-FAIR a foolish, weak person; one easily imposed upon ...1777 Eng. dial.
• SART-POLL a foolish, weak person; one easily imposed upon; a good-for-nothing fellow ...1867 Eng dial.
• SATEPOLL a foolish, silly, or stupid person; a simpleton ...1867 Eng. dial.
• SAUSAGE someone foolish or gullible; used as a gently reproving term of address ...1982 UK sl.
• SAWN a foolish person ...1953 Aust. sl.
• SAWN(E)Y a simpleton, a fool, a stupid fellow; a soft, good-natured fellow ...a1700 colloq.
• SCART a saving, industrious person; a niggard; a villain; a fool ...1895 Sc. & Eng. dial.
• SCHLEMASEL, SCHLEMAZEL a fool, esp. an unfortunate, an incompetent ...L19 sl.
• SCHLEMBO a fool ...2000s sl.
• SCHLEMIEL, SCHLEMIHL, SHLEMIEL a fool; a clumsy person; a gullible person; an ineffectual or incompetent person ...1892 sl., chiefly US
• SCHLEP(P), SHLEP a foolish person ...1939 sl., chiefly US
• SCHLEPPER, SHLEPPER a foolish person ...1954 sl., chiefly US
• SCHLOOMP, SHLOOMP a foolish person ...1948 sl., orig. & chiefly US
• SCHLUB, SHLUB an oaf or dolt; a fool ...1964 US sl.
• SCHLUCK, SHLUCK a clumsy, uncoordinated fool ...Brit. sl.
• SCHLUMP, SHLUMP a foolish person ...1948 sl., orig. & chiefly US
• SCHMENDRIK, SHMENDRIK a foolish person ...1944 US sl.
• SCHMO, SHMO a foolish person ...1948 sl., chiefly US
• SCHMOCK, SHMOCK a stupid person; a fool; oaf; ...20C US sl.
• SCHMUCK, SHMUCK a foolish person ...1892 sl., chiefly US
• SCISSOR one regarded as foolish, incompetent, or inexperienced ...1916 Amer. dial.
• SCISSORS-BILL one regarded as foolish; an ineffectual, incompetent, or inexperienced  person ...1871 sl., chiefly US
• SCIZZOR-BILL one regarded as foolish, incompetent, or inexperienced ...1940 Amer. dial.
• SCRUB a fool, a stupid person, a dumb individual ...1980s US Black sl.
• SEMOLIA a fool; a stupid person ...1890s US Black sl.
• SHALLOW-PATE a person having no depth of intellect or understanding; a foolish or empty-headed person ...1600
• SHEEPSHEAD † a foolish or stupid person ...1542
• SHITTY-WATTY a weak-headed, foolish person ...B1900 Eng. dial.
• SHLEMOZZLE a fool, esp. an unfortunate, an incompetent ...L19 sl.
• SHOON a fool; a bumpkin; a lout ...19C cant
• SIDE-SIM a fool; a simpleton ...E17 sl.
• SILLIKEN, SILLIKIN a fool, a simpleton ...1860 sl.
• SILLY a silly or foolish person ...1858 colloq.
• SILLY-ARSE a fool ...1943 Aust. sl.
• SILLY ASS a foolish or stupid person ...1608
• SILLY BILLY a fool, a simpleton ...1834 sl.
• SILLY BOLLOCK(S) a contemptible fool; an idiot ...1999 UK sl.
• SILLY CUNT a fool ...2000 UK sl.
• SILLY GOOSE a fool ...Bk1995 US sl.
• SILLY LEGS a term of mild abuse aimed at someone behaving like a fool ...Brit. sl.
• SILLYPOP a fool; a foolish, flighty woman ...L19 sl.
• SILLY WILLY a fool; a simpleton ...M17 sl.
• SIM a fool; a simpleton; a confidence trickster's dupe ...20C Aust. criminals' sl.
• SIMKIN * a fool; a simpleton ...a1700
• SIMON a fool; a soft-head ...Bk1891 sl.
• SIMP a fool, a simpleton, an oaf, a stupid or dull person; a dim-witted or backward person ...c1910 sl., orig.
• SIMPKIN a fool; a simpleton ...1861 rare
• SIMPLE an ignorant or foolish person ...1643
• SIMPLER a simple or foolish man much given to lust ...L16 sl.
• SIMPLE SIMON a silly fellow; a credulous gullible person; a fool, a simpleton ...1785 sl.
• SINGLE-TEN a very foolish, silly fellow ...a1700 sl.
• SIR ANTHONY (BLUNT) a fool; a despicable fool ...1979 UK rhyming sl. for 'cunt'
• SIZZER one regarded as foolish, incompetent, or inexperienced ...1932 Amer. dial.
• SKEEZIX a fool ...1975 US sl.
• SKITTER-WIT a flighty person; a foolish, harebrained fellow; a scatterbrain ...1886 Eng. dial.
• SKITWIT a soft, foolish, scatterbrained person ...B1900 Eng. dial.
• SLOW-COACH a fool; a soft-head ...Bk1891 sl.
• SNORKER a contemptible fool ...1977 US sl.
• SOAP a fool, a simpleton ...1950s Aust. sl.
• SOFT-HORN a fool; a soft-head ...Bk1891 sl.
• SOFTIE, SOFTYa person who is sentimental, weakly foolish, or lacking in physical endurance ...1886
• SOP a fool; a soft-head ...Bk1891 sl.
• SOPPY DATE a foolish or silly person ...1914 UK sl.
• SPACE CADET a foolish person; a person who is always silly or giddy ...1973 sl.
• SPACKHEAD a fool; an eccentric person ...2003 UK juvenile sl.
• SPALT †* a silly or foolish person ...1639
• SPANGLE a fool; a very stupid person ...2001 Sc. juvenile sl.
• SPANNER a fool; a stupid person; an idiot ...1987 sl.
• SPANNER-HEAD a fool; a stupid person; an idiot ...1990 Aust. sl.
• SPARKY a fool; a mentally handicapped person ...2003 UK sl.
• SPAS, SPAZ(Z) (derogatory) a spastic person; an ineffectual or incompetent person; a fool; an idiot; a stupid person; a clumsy, unattractive person ...1965 sl.
• SPASTIC - (offensive) one who is uncoordinated, ineffectual, or incompetent; a fool; an idiot; a stupid person; a clumsy, unattractive person ...1968 sl.
• SPAZ-WIT a fool, an idiot, a stupid person .,..1998 UK sl.
• SPOON a fool, a simpleton ...L18 sl.
• SPOONEY a fool, a simpleton ...L18 sl.
• SPOONY a fool, a simpleton ...L18 sl.
• SQUIRE, THE a simpleton, a fool ...L17 sl.
• S.S. a fool; (Sammy Soft) ...c1840 sl.
• STEAMER a fool; a victim ...1932 UK sl.
• STEAM TUG a fool; a victim ...1932 UK rhyming sl = mug
• STIFFY a foolish person ...1965 US sl.
• STRACKLE-BRAIN a giddy, thoughtless person; a simpleton, a fool; a good-for-nothing ...1877 Eng. dial.
• STRUT-NODDY a mincing fool ...Bk1904 sl.
• STUB a fool; an oaf...1632-74 sl.
• STUMP an oaf; a fool; a blockhead...19C Brit. sl.
• STUPE a foolish person ...1762 sl.
• SUCK-EGG a fool, a silly person, a stupid fellow ...1609 Eng. dial. & sl.
• SUMPH a fool, a blockhead ...1682 Sc. & Eng. dial.
• TACK a fool ...1974 US Black sl. 
• TAME CAT a person who is made a convenience by his friends; a foolish fellow, a simpleton ...1885
• TAME-FELLOW † a person who is made a convenience by his friends; a foolish fellow, a simpleton ...a1700
• TAME-GOOSE † a foolish fellow; a simpleton ...1605
• TAMMY a simpleton, a fool ...Bk1905 Eng. dial.
• TAMMY-NORRY a simpleton, a foolish person ...Bk1905 Eng. dial.
• TAPLOCH † a giddy, foolish girl ...1824 Sc.
• TAPPY a foolish, giddy, awkward, idle, or slovenly girl ...1824 Sc.
• TARD a dolt; a fool; a stupid person ...Bk1994 US teen & college sl.
• TARRY ROPE a fool ...1944 rhyming sl. for 'dope'
• TART a fool, male or female ...1999 sl.
• TASS(E)Y, TAZIE, TAZZY a mischievous child; a foolish, romping girl; a silly fellow ...1808 Sc. & Eng. dial.
• TATA a foolish person ...1966 UK sl.
• TATARAM a foolish old man, esp. one with sex on his mind ...1996 W. Indies
• TAUPIE, TAWPIE, TAWPY a foolish, giddy, scatterbrained, untidy, awkward, or careless person; an idle or slovenly person; generally applied to young women ...1728 Sc.
• TAWPLOCH † a giddy, foolish girl ...Bk1824 Sc.
• TETAW a simpleton, a fool ...Bk1905 Eng. dial.
• THICK a foolish person ...1857 sl., orig. schoolchildren's usage
• THICKHEAD a fool; a soft-head ...Bk1891 sl.
• THICKIE a foolish person ...1968 sl.
• THICKO a foolish person ...1976 sl.
• THITER a foolish fellow; an idiot ...Bk1905 Eng. dial.
• THOMAS a fool, a simpleton ...1934 Sc.
• THRUM-YED a foolish fellow ...Bk1905 Eng. dial.
• TIN EAR a fool; a simpleton ...1930s Aust. & US sl.
• TIN HAT a fool ...1960s rhyming sl. for 'prat'
• TIT a foolish person ...1947 sl.
• TITTLE-GOOSE a foolish, tattling person; a telltale, a foolish blab ...1807 Eng. dial.
• TOM a man, esp. a foolish one ...M16 sl.
• TOM FARTHING a fool, a simpleton ...1689
• TOM FOOL a foolish or stupid person; one who behaves foolishly ...1721
• TOMMY a simpleton, a fool ...1829
• TOMMY-NODDY a foolish or stupid person ...1828
• TOM-NODDY a foolish or stupid person; a blockhead, dunce, dolt, simpleton ...1828
• TOM TUG a fool; a soft-head ...Bk1891 sl.
• TONEY, TONY † a foolish person; a simpleton ...1654 sl.
• TONK a foolish person ...1941 sl., chiefly Aust.
• TOOL a fool ...sl.
• TOOT an idle or worthless person; a shiftless, lazy person; a simpleton, a fool; an oaf ...1888 Eng. & Amer. dial.
• TROANT † a foolish, idle person; a lazy loiterer ...1746 Eng. dial.
• TRONK an idiot; a foolish person ...1970s UK teen sl.
• TRONK-HEAD an idiot; a foolish person ...1970s UK teen sl.
• TUNKLEHEAD a fool ...1941 Amer. dial.
• TURKEY an idiot, a fool ...Bk1995 US sl.
• TWALLY an idiot; a fool ...1996 Sc. sl.
• TWERP, TWIRP a foolish person ...1874 sl.
• TWINK a jerk; an incompetent fool ...20C US sl.
• TWIT a foolish person ...1934 sl., chiefly Brit.
• UDDER a despised, disrespected or foolish woman ...2001 UK sl.
• UGMA a fool; a (potential) victim ...1956 Aust. criminals' sl.
• UGMAY a 'sucker', a dupe, a gullible person; a fool, or a stupid person ...1918 US Pig Latin for 'mug'
• UM-CHAW a doltish, naive person; a foolish or stupid person; a dupe, a gullible person ...1910 Pig Latin for 'chump' 
• UMPCHAY a doltish, naive person; a foolish or stupid person; a dupe, a gullible person ...1910 Pig Latin for 'chump' 
• UNCHAGHE † a foolish or wanton woman ...1534
• UNCONSCIOUS a fool ...1920s US college sl.
• UNWISEMAN † a fool, a simpleton ...1400
• UTZPAY a fool, an idiot ...1930s Pig Latin for 'putz' 
• VEAL a fool, a simpleton ...c1642 UK sl.
• WACKER, WHACKER a fool; a stupid person ...1965 Aust. sl.
• WACKY a fool, simpleton, blockhead ...Bk1903 Eng. dial.
• WAD a fool, an idiot, an unpleasant person ...1900 sl., orig. US college usage
• WAD-WASTE a term of abuse; a fool, an idiot, an unpleasant person ...1981 sl., orig. US college 
• WAFFLE-BAGS a foolish person who talks much, and foolishly ...1884  Eng. dial.
• WALLY a foolish person ...1969 Brit. sl.
• WANT-WIT one who lacks wit or sense; a fool ...1448-9
• WARB a fool, a simpleton ...1955 Aust. sl. 
• WATERHEAD a foolish person ...1960s sl.
• WATTY a simpleton; an indiscreet or foolish person ...B1900 Eng. dial.
• WAZZOCK a foolish person ...1983 Brit. sl.
• WEAPONHEAD a foolish person ...1980s Aust. prison sl.
• WET an ineffectual, weak, foolish person ...1930s sl., orig. UK juvenile usage
• WET END an ineffectual, weak, foolish person ...1930s sl., orig. UK juvenile usage
• WETSO an ineffectual, weak, foolish person ...1930s sl., orig. UK juvenile usage
• WHACKER a fool ...1960s Aust. sl.
• WIDGEON † applied to a person, in allusion to the supposed stupidity of the bird; a fool, a simpleton ...1612
• WIGEON a fool, a simpleton ...E17 arch.
• WILF a fool ...Bk2004 UK sl.
• WILLY WONKA a fool ...1998 UK sl. for 'plonker'
• WISE MAN OF GOTHAM, A  a foolish person ...1737
• WITLING a fool, a simpleton ...Bk1905 Sc.
• WITTY a fool; a mentally retarded person ...1940 Amer. dial.
• WOMBLE a foolish, clumsy, or unfortunate person; a socially inept person ...1985 UK sl.
• WOODCOCK a gullible fool; an oaf ...15C
• WOODENTOP a fool; a slow-witted person ...1983 Brit. sl. 
• WOZZ a fool; an idiot ...Brit. sl.
• WOZZLE a fool; an idiot ...Brit. sl.
• WUL a fool ...Brit. sl.
• WULBERT a fool ...Brit. sl.
• YABO a fool ...1925 sl.
• YACK, YAK a fool; a stupid fellow; an oaf; an innocent person; a dope ...c1920 US sl. 
• YAP a foolish person; a simpleton; one slightly weak in intellect ...c1894
• YAPPY a foolish person; one slightly weak in intellect ...Bk1905 Eng. dial.
• YAP-STICK a foolish person; one slightly weak in intellect ...Bk1905 Eng. dial.
• YARD DOG a fool; a gullible person ...1930s US Black sl.
• YASHA an idiot; a fool; a dolt ...Bk1972 homosexual sl. 
• YAUP, YAWP one who has a vacant stupid look; a fool, an oaf, a yokel ...1896 Sc.
• YAWKY a foolish or maladroit person ...Bk1887 Eng. dial.
• YAWNAX a stupid person; a fool; a lazy, uncouth person; a boor ...1870 Eng. dial.
• YAWN(E)Y, YORNEY a stupid, lazy, sleepy person; a fool ...1777 Eng. dial.
• YAWNUP a stupid person; a fool; a lazy, uncouth person; a boor ...1870 Eng. dial.
• YAWNUPS a stupid person; a fool; a lazy, uncouth person; a boor ...1870 Eng. dial.
• YAWNUX a stupid person; a fool; a lazy, uncouth person; a boor ...1870 Eng. dial.
• YAZZIHAMPER † a farmer; a rustic; a fool, a sucker ...1933 criminals' sl.
• YERQUICK an absolute fool; a really dumb person ...2001 Aust. sl.
• YOB * a fool; a naive, gullible, or unintelligent person; a dupe; also, an unsophisticated person; a country bumpkin ...1886 chiefly Aust. & NZ
• YOBBO a foolish, unsophisticated idiot ...Bk1988 Aust. sl.
• YOCKER a foolish person or bumpkin ...Bk2002 criminals' sl.
• YOK a man; a fool. a chump ...1934 sl.
• YONNACK a fool, a harebrained fellow ...Bk1887 Eng. dial.
• YOTZ a fool, an idiot ...1983 US sl.
• YOYO an unpredictable or inconsistent person whose moods and actions go up and down; hence, a fool; an idiot, a dolt; a stupid person; an obnoxious person; an incompetent, or undesirable person; a jerk ...1959 US sl.
• YUCK, YUK  a fool; a stupid fellow; an oaf; an innocent person; a rustic ...1943 sl., orig. US
• YUTZ a fool, an idiot; a simpleton; a failure ...1983 US sl.
• ZAMMY a simpleton, a fool; an ill-natured fellow; an effeminate weakling; a lunatic ...1876 Eng. dial.
• ZANY a fool, a simpleton ...a1784
• ZAPE a blockhead; a fool ...Bk1882 Eng. dial.
• ZAPP a simpleton; a blockhead; a fool; a dunce ...1817 sl.
• ZAPY a blockhead; a fool ...Bk1882 Eng. dial.
• ZATENFARE a foolish, weak person; one easily imposed upon ...1777 Eng. dial.
• ZHLOB an oaf or dolt; a fool, a moron; a boorish, insensitive person; a coarse person, a slob ...1950 US sl.
• ZHLUB an oaf or dolt; a fool, a moron; a boorish, insensitive person; a dull, unpolished person, usually a male ...1950 US sl.
• ZIB a nincompoop; a fool, a sucker; an oaf; a stupid person with unknown political or personal opinions ...1934 US sl., chiefly criminals' usage
• ZIP a worthless person; a person who amounts to zero; an insignificant person; an unpleasant person with no good qualities; a fool; a sucker ...1971 US sl.
• ZIPALID a complete fool ...1970s US sl.
• ZIPPERHEAD (derogatory) a stupid person; a fool ...1967 US sl.
• ZIPPERLID a complete fool ...1970s sl.
• ZIPPO an insignificant person; an unpleasant person with no good qualities; a fool; a sucker ...1987 US sl.
• ZIP SACK an insignificant person; an unpleasant person with no good qualities; a fool; a sucker ...1982 US sl.
• ZIRCON a fool ...1968 US sl.
• ZOB * a weak or contemptible person; a fool; a good-for-nothing; a worthless person; a nobody ...1911 US sl.
• ZOKE a fool, a dolt ...Bk1886 Eng. dial.
• ZOKEY a sawney; a foolish person ...Bk1855 Eng. dial.
• ZONK a fool; a dolt; an idiot ...Bk1988 Aust. & NZ
• ZOOMER an energetic fool ...2000 UK sl.
• ZOT(E)Y - a fool; an idiot ...Bk1855 Eng. dial.
fool - verbs  (also see BEFOOL, FOOL ABOUT ) (includes foolish)
• ACE OUT to fool someone; to swindle someone ...1933 US sl.
• ACT THE ANGORA to play the fool ...1942 Aust. sl.
• ACT THE GIDDY GOAT to behave foolishly ...L19 sl.
• ACT THE GOAT to behave foolishly ...L19 sl.
• ACT THE HOG to play the fool ...1900s sl.
• ACT THE MAGGOT to play the fool ...1937 Irish sl.
• ACT THE MONKEY to play the fool ...1900s sl.
• ACT THE JINNIT to play the fool; to act irrationally ...20C Irish sl.
• ACT THE NIGGER 1. (derogatory) to play the fool ...M19 US sl.
  2. to act in a manner White racists expect of Black people, i.e. foolish, subservient, clownish ...M19 US Black sl.
• ACT THE PRICK to behave foolishly ...1980s sl.
• ADOLESCENTURATE † to play the boy, or fool ...1626
• ASS OUT to make a fool of oneself ...1990s US college sl.
• BAFFLE † to hoodwink, to gull, to cheat; to humbug; to make a fool of ...c1590
• BAMFOOZLE to fool or swindle; to confuse ...1851 Amer. dial.
• BEDAFF † to make a fool of, to make foolish ...c1386
• BEDAW to make a fool of ...a1529
• BEGAB † to fool with words, to mock, to deceive, to delude; to impose upon ...1297
• BELIEVE THE MOON IS MADE OF CHEESE to believe firmly something astounding, impossible, or absurd; hence, to be a fool ...18C colloq.
• BE NOT AS GREEN AS ONE IS CABBAGE-LOOKING be less than a fool than might be assumed ...colloq.
• BE WRONG IN ONE'S GARRET to be foolish or wanting in intellect, or suffering from temporary delirium ...1869 sl.
• BIG-ASS to make a fool of ...1984 US sl.
• BLIND to confound or stump someone; to fool ...1916 Amer. college usage
• CHILL OUT to stop acting foolish ...1981 US Black sl.
• CHUMP 1. to trick, to deceive; to make a fool of someone ...1920s sl.
2. to act like a fool; to be exploited ...1960s US Black sl.
• CHUMP OFF to act like a fool ...1930s US Black sl.
• CHUMP OUT to trick, to deceive; to make a fool of someone ...1920s sl.
• CLEAVE THE CLOUDS to act foolishly and to no purpose ...B1900
• COME ON ONE'S GUAVA to make a fool of oneself ...1970s S. Afr. sl.
• COME THE ABDABS to fool someone ...1940s sl.
• COME THE OLD ABDABS to hoax, to fool ...1940s sl.
• CONFISCATE THE MACAROON to 'take the biscuit'; to be the most remarkable or foolish of its kind ...c1918 Brit. sl.
• COUGH ONE A DAW † to make a fool of, to befool ...a1529
• CRAP AROUND to waste time; to behave foolishly or aimlessly ...1935 US sl.
• CROWN WITH A MAROTTE † to make a fool of ...1630
• CUDDLE AND KISS to make a fool of, to 'take the piss' ...1992 UK rhyming sl.
• CUT A BIG GUT to do something foolish ...Bk1942 Amer. sl.
• DAFF to play the fool ...1535 chiefly Sc.
• DESERVE THE BAUBLE † to make a fool of ...1606
• DO ONESELF to make a fool of oneself; to embarrass oneself ...1980s US sl.
• DUD to fool or deceive; to swindle ...1970 Aust. sl.
• DUKE to fool; to deceive ...1975 US sl.
• EAT ONE'S NAILS to do something foolish ...E18 sl.
• FAKE to trick, to fool; to cheat; to swindle; to deceive ...1859 sl.
• FAKE OUT to fool an opponent with a feint; hence, generally, to bluff, to fool; to get the better of; to dupe, to deceive ...1949 Amer. sl., orig. football & basketball usage
• FART ABOUT to dawdle, to mess around, to potter, to waste time in trifling activity; to behave foolishly or aimlessly ...1910s sl.
• FART AROUND to dawdle, to mess around, to potter, to waste time in trifling activity; to behave foolishly or aimlessly  ...1969 sl.
• FATUATE to become silly, to act foolishly, to play the fool ...1656 arch.
• FILL to fool; to provide with misinformation ...1968 Amer. dial.
• FILL UP to fool; to provide with misinformation ...1879 Amer. dial.
• FLAM to swindle, to fool, to deceive ...1637
• FLUMMOX, FLUMMUX to fool, to confuse, to overcome by trickery; to bewilder ...1837 sl.
• FOOLIFY † to make a fool of; to befool ...1581 obs. exc. Eng. dial.
• FOOTLE to talk or act foolishly; to do anything in a feeble or ineffectual manner; to dawdle, to trifle, to potter; to idle, to waste time ...1892 sl.
• GAME † to befool, to jeer at, to mock, to delude ...1698 UK sl.
• GAMMON to deceive, to fool, to talk humbug,...1812
• GIVE A RIDE to deceive, to fool, to trick, usually for financial gain ...1920s sl.
• GIVE SOMEONE THE ABDABS to fool someone ...1940s sl.
• GIVE SOMEONE THE GUY to make a fool of someone; to tease ...19C sl.
• GIVE SOMEONE THE OLD ABDABS to fool someone ...1940s sl.
• GIVE THE BAUBLE † to make a fool of, to befool ...1599
• GREEN to tease, to make a fool of; to annoy with practical jokes; to outwit ...1923 Amer. dial.
• GREEN ON to tease, to make a fool of; to annoy with practical jokes; to outwit ...1887 Amer. dial.
• GREEN OUT to tease, to make a fool of; to annoy with practical jokes; to outwit ...1887 Amer. dial.
• GUCK † to trifle; to play the fool ...c1560 Sc.
• GYPE to play the fool; to mess around ...1825 Sc. & Eng. dial.
• HAIVER to talk in a foolish, incoherent manner ...1816 Sc.
• HALLOCK to behave in a foolish, noisy way ...Bk1905 Sc.
• HAVEREL to talk nonsense, to make a fool of ...1822 Sc. & Eng. dial.
• HOLD A LOOKING-GLASS TO A MOLE to act foolishly and to no purpose ...B1900
• IDIOTIZE to make a fool of; to befool ...1831
• JACK ACT to play the fool ...1920s Irish sl.
• JEFF to talk, to chatter, esp. to seduce, to fool or deceive with a 'line' ...1960s US Black sl.
• JERK SOMEONE'S CHAIN to deceive, to fool, to victimize ...Amer. sl.
• JERK SOMEONE'S STRING to deceive, to fool, to victimize ...Amer. sl.
• LANT to jeer at; to gibe; to make a fool of ...1861 Sc.
• LARK to play, esp. the fool; to be mischievously merry; to go on the spree ...1813 colloq.
• LAY IT OVER to fool, to deceive ...1878 Amer. sl.
​• LOSE OUT to be swindled or merely fooled ...L19 Aust. sl.
• MACKY-MOON to play the fool ...B1900 Eng. dial.
• MAFFLE to act or talk in a foolish way ...Bk1905 Eng. dial.
• MAKE A MONKEY (OUT) OF to make a fool of; to deceive, to dupe; to ridicule ...1767 sl., orig. US
• MONK to make a fool of ...1916 Amer. dial.
• MUCK ABOUT to waste time; to behave foolishly or aimlessly ...1856
• MUCK UP to play the fool ...c1910 Aust. sl.
• NAFFLE to trifle away time; to potter about; to loiter; to act foolishly ...1796 Sc. & Eng. dial.
• NANNICK to play the fool; to play when one should be working; to idle away one's time; to fidget ...Bk1905 Eng. dial.
• NANNOCK to play the fool; to play when one should be working; to idle away one's time; to fidget ...Bk1905 Eng. dial.
• NICK to fool ...1593
• NIFF-NAFF to trifle; to toy; to take finicking trouble; to talk or act foolishly or aimlessly ...1728 Sc. & N. Eng. dial.
• NONNOCK to play the fool; to play when one should be working; to idle away one's time; to fidget ...Bk1905 Eng. dial.
• NONNUCK to play the fool; to play when one should be working; to idle away one's time; to fidget ...Bk1905 Eng. dial.
• OAF to act in a foolish, childish manner; to play the fool ...1882 Sc. & Eng. dial.
• OAF ABOUT to act in a foolish, childish manner; to play the fool ...1882 Sc. & Eng. dial.
• PACK IT IN to stop talking; to stop fooling or some foolish practice ...c1925 Services' sl.
• PACK IT UP to stop talking; to stop fooling or some foolish practice ...c1925 Services' sl.
• PAPPY SHOW to make a fool of someone ...L19 W. Indies
• PIDDLE ABOUT to behave foolishly, and esp. in a time-wasting way ...1545 sl.
• PIDDLE AROUND to behave foolishly, and esp. in a time-wasting way ...1545 sl.
• PISS ABOUT to waste time; to behave foolishly or aimlessly ...1961 sl.
• PISS AROUND to behave foolishly, and esp. in a time-wasting way ...1961 Brit. & Aust. sl.
• PLAY HORSE to play the fool or engage in horseplay ...1892 US sl.
• PLAY OFF ON to deceive, to fool, to trick ...1863 Amer. dial.
• PLAY SILLY BLEEDERS to waste time; to behave foolishly or aimlessly ...1961 sl.
• PLAY SILLY Bs to waste time; to behave foolishly or aimlessly ...1961 sl.
• PLAY SILLY BUGGERS to waste time; to behave foolishly or aimlessly ...1961 sl.
• PLAY SOMEONE FOR A CHINAMAN (now considered offensive) to treat as a fool ...1873 Amer. sl.
• PLAY THE GOAT to act the fool ...L19 sl.
• PLAY THE JACK to act the fool ...Bk1896 sl.
• PLAY THE MONKEY to play the fool ...1900s sl.
• PLAY THE NANNY-GOAT to behave like a fool; to play foolish tricks ...1900 Eng. dial.
• POPPY SHOW to make a fool of someone ...L19 W. Indies
• PRAT ABOUT to behave foolishly, and esp. in a time-wasting way ...1961 Brit. sl.
• PULL SOMEONE'S CHAIN to deceive, to fool, to victimize ...Amer. sl.
• PULL SOMEONE'S PLONKER to fool someone; to tease someone; to take a liberty with someone...2000 UK sl.
• PULL SOMEONE'S STRING to deceive, to fool, to victimize ...Amer. sl.
• PULL SOMEONE'S TIT to good-naturedly hoax or deceive someone; to make a fool of someone ...1959 Aust. sl.
• PUPPY SHOW to make a fool of someone ...L19 W. Indies
• PUT A ROPE TO THE EYE OF A NEEDLE to attempt the impossible or absurd; to act foolishly and to no purpose ...B1900
• PUT THE CAP ON SOMEONE to fool them ...1966 Amer. dial.
• RAG ABOUT to fool about ...20C sl., orig. & chiefly university
• RATTLE SOMEONE'S CHAIN to deceive, to fool, to victimize ...Amer. sl.
• RATTLE SOMEONE'S STRING  to deceive, to fool, to victimize ...Amer. sl.
• ROAST SNOW IN A FURNACE to attempt the unnecessary or absurd; to act foolishly and to no purpose ...1883 sl.
• RUN THE HOG to play the fool ...1900s sl.
• SAWNEY to act the sawney, to fool ...B1900
• SEEK A NEEDLE IN A BOTTLE OF HAY to attempt an extremely difficult, impossible, or foolish task ...1690
• SEEK A NEEDLE IN A TRUSS OF HAY to attempt an extremely difficult, impossible, or foolish task ...1711
• SELL AN OX TO CATCH A HARE to act foolishly ...B1900
• SELL ANY ONE A BARGAIN † to make fool of him, to 'sell' him ...1588
• SHOW A TRICK to outwit, to fool, to deceive ...1982 NZ sl.
• SIMP to act like a fool ...1960s US Black sl.
​• SLIP ON ONE'S GUAVA to make a fool of oneself ...1970s S. Afr. sl.
• SPOOF to hoax, to fool, to trick ...L19 sl.
• STOOGE to fool, to deceive ...1990s Aust. sl.
• STRING to fool or hoax; to deceive, to dupe ...1812 sl., chiefly US
• TAKE FOR A RIDE to deceive, to fool, to trick, usually for financial gain ...1920s sl.
• TAKE FOR A TROT to deceive, to fool, to trick, usually for financial gain ...1920s sl.
• TAKE THE PISS OUT OF of a person: to act absurdly, to play the fool ...1990 sl.
• TAKE THE TA-TA to make a fool of someone; to pull someone's leg, to tease ...1992 UK rhyming sl. for 'take the piss' (take the ta-ta kiss)
• TAKE THE TA-TA KISS to make a fool of someone; to pull someone's leg, to tease ...1992 UK rhyming sl. for 'take the piss'
• TALK TURKEY to talk foolishly ...E19 sl., orig. US
• TATTER to make a fool of anyone ...Bk1905 Eng. dial.
• TEACH IRON TO SWIM to act foolishly and to no purpose ...1809
• TOM-FOOL to play the fool ...1825
• TONY †* to make a fool of; to fool, to cheat, to swindle ...a1652
• WALK DOWN ONE'S BACK to take one in; to make a fool of one ...1867 Eng. dial.
• WEAR THE BELLS to act the fool ...1931 Amer. dial.
• WRITE ON THE SURFACE OF THE SEA to act foolishly and to no purpose ...B1900
• YANK SOMEONE'S CHAIN to deceive, to fool, to victimize ...Amer. sl.
• YANK SOMEONE'S STRING to deceive, to fool, to victimize ...Amer. sl. Dict
• YUCK IT UP to behave foolishly, and esp. in a time-wasting way ...1961 sl., chiefly Amer.
• YUK IT UP to behave foolishly, and esp. in a time-wasting way ...1961 sl., chiefly Amer.
fool - phrases 
• FOOL'S A MONKEY'S MASTER, A said to one who calls another a fool ...B1900 Eng. dial.
• HE DOESN'T KNOW IF HIS ARSEHOLE IS BORED OR PUNCHED he's a complete fool ...E20 sl.
• I DIDN'T COME DOWN IN THE LAST SHOWER I'm not stupid; don't take me for a fool ...20C Aust. sl.
• I DIDN'T COME DOWN IN THE LAST SHOWER OF RAIN I'm not stupid; don't take me for a fool ...20C Aust. sl.
• I DIDN'T FALL OFF A CHRISTMAS TREE I'm not stupid; don't take me for a fool ...1940s sl.
• NOT SO GREEN AS I'M CABBAGE-LOOKING I'm not such a fool as I may appear ...L19 sl.
• THERE ARE MANY WAYS OF DRESSING CALVES' HEADS many ways of saying or doing a foolish thing; a simpleton has many ways of showing his folly; or, generally, if one way won't do, we must try another ...Bk1891 sl.
• THERE ARE NO FLIES ON HIM he is no fool
 
FOOL ABOUT, FOOL AROUND - nouns
• FUNNY BUSINESS nonsense; fooling around; later, action or behaviour that is deceptive, dishonest, or otherwise suspect ...1882 colloq.
fool about, fool around - person
• FART-OFF a person who shirks responsibilities; a loafer; one who always fools around ...1942 Amer. sl.
• PISS ARTIST a drunkard; a person who fools about; a feckless or irresponsible person ...1962 colloq.
fool about, fool around - verbs 
• ANTIC to fool around, to play ...1976 Amer. dial.
• ARSE ABOUT to idle, to fool about; to waste time ...1664 Brit.
• ARSE AROUND to idle, to loaf, to loiter, to fool about, to act irresponsibly, to trifle ...1664
• ASS AROUND to fool around, to loiter, to waste time; to wander aimlessly; to be idle; to act irresponsibly; to trifle ...1914 Amer. sl.
• ASSEN AROUND to fool around; to loiter; to waste time; to be idle ...1966 Amer. dial.
• BOLLIX AROUND to fool around ...c1960 Amer. dial.
• BUGGER ABOUT to behave foolishly, and esp. in a time-wasting way ...1929 Brit. & Aust. sl.
• BUGGER AROUND to behave foolishly, and esp. in a time-wasting way ...1929 Brit. & Aust. sl.
• CAT to gad about; to fool around ...1938 Amer. dial., chiefly among Blacks
• CAT AROUND to gad about; to fool around ...1938 Amer. dial., chiefly among Blacks
• FADE to fool around or tinker with something or someone ...1990s US Black teen sl.
• FAFF to mess about, restlessly and ineffectually, wasting time, often while something quite urgent needs attention; to play or fool around, to waste time ...c1930
• FAFF AROUND to mess about; to waste time on matters of no importance; to play or fool around ...1874 UK sl.
• FAFF ABOUT to behave foolishly, and esp. in a time-wasting way ...1874 sl., orig. Eng. dial.
• FANDANGLE to hang about, to trifle, to waste time, to 'fool' around ...1892 Ireland
• FART ABOUT to waste time; to behave foolishly or aimlessly ...1900 sl.
• FART AROUND to dawdle, to mess around, to potter, to waste time in trifling activity; to behave foolishly or aimlessly  ...1931 sl.
• FART OFF to fool around; to shirk one's duties; to blunder through inattention; to procrastinate ...1968 Amer. sl.
• FIDDLE-DEE-DEE AROUND to meddle, to fool around ...1963 Amer. dial.
• FIDDLE-FART to fool around, to waste time. to loaf, to dawdle, to shirk responsibility ...1975 Amer. dial.
• FIDDLE-FART AROUND to fool around, to waste time. to loaf, to dawdle, to shirk responsibility ...1972 Amer. sl.
• FIDDLE-FOOT AROUND to fool around, to move restlessly ...1963 Amer. dial.
• FIDDLEFUCK AROUND to fool around, to waste time. to loaf, to dawdle, to shirk responsibility ...1984 Amer. dial.
• FOOZLE ABOUT to fool around ...1930s sl.
• FUCK ABOUT to behave foolishly, and esp. in a time-wasting way ...1922 sl.
• FUCK AROUND to behave foolishly, and esp. in a time-wasting way ...1922 sl.
• FUTZ AROUND to behave foolishly, and esp. in a time-wasting way ...1929 US sl.
• GAY-CAT to gad about; to fool around ...1938 Amer. dial., chiefly among Blacks
• GET OUT OF ONE'S RINK to sow wild oats ...Bk1903 colloq.
• GOOF to behave foolishly, and esp. in a time-wasting way ...1929 sl., chiefly US
• GOOF AROUND to behave foolishly, and esp. in a time-wasting way ...1929 sl., chiefly US
• GOOF OFF to behave foolishly, and esp. in a time-wasting way ...1943 sl., chiefly US
• HACK to socialize idly; to gad or fool about; to waste time ...1888 Amer. sl.
• HACK ABOUT to socialize; to fool about ...1920s US college sl.
• HACK AROUND to socialize idly; to gad or fool about; to waste time ...1923 US college sl.
• HACK OFF to idle; to loaf; to lounge; to go about aimlessly looking for distraction; to gad or fool about; to waste time ...1920s US college sl.
• HORSE to indulge in rough jokes or horseplay; to fool around; hence, to waste time in trifling activity; also, to philander (now usually with 'around')...1900 US sl.
• JACKASS AROUND to fool about; to mess around; to waste time playing around ...1927 colloq.
• JACK OFF to fool around, to do nothing ...1940s US sl.
• JAG AROUND to fool around; to goof off ...1968 Amer. dial.
• JAZZ AROUND to fool around ...1917 Amer. dial.
• KICK THE GONG to fool around ...1945 US sl.
• LALLIGAG, LALLYGAG to dawdle, to dally, to be idle; to waste time out of ineptitude or design; to fool about ...1862 US sl.
• LOLLIGAG, LOLLYGAG to dawdle, to dally, to fool about; to be idle; to waste time out of ineptitude or malicious design ...1862 US sl.
• LOON to fool about like a lunatic ...1960s Brit. criminals' sl.
• LOON ABOUT to fool about like a lunatic ...1979 Brit. sl.
• LOSE TIME to waste time; to fool around ...1967 Amer. dial.
• MEDDLE AROUND to fool around; to go about aimlessly looking for distraction ...1968 Amer. dial.
• MESS to dawdle or putter; to fool around; to kid around, to tease ...1966 Amer. dial.
• MESS WITH to become involved with; to use; to fool around with ...19C US sl.
• MONK to tinker, trifle, or fool around; to tamper or interfere with surreptitiously ...1889-90 Amer. sl.
• MONKEY to tinker, trifle, or fool around; to fritter away one's time; usually used with 'with' ...1877-78 Amer. sl.
• MONKEY AROUND to act without purpose; to play around ...1884 Amer. colloq.
• MONKEY-FART AROUND to waste time; to fool about ...a1970 Amer. sl.
• MUCK ABOUT to fool around; to trifle with ...1856 sl.
• MUCK AROUND to fool around ...1856 UK sl.
• NUTS to fool around ...1941 Amer. sl.
• PISS-ARSE ABOUT to fool about; to waste time ...c1920 army sl.
• SHUCK to be deceptive or evasive; to tell tall tales or lies; to fool around, to tease ...1968 Amer. dial.
• SHUCK AND JIVE to act irresponsibly; to fool around ...1970 Amer. dial.
• SILLY to act foolishly; to fool about ...1877 chiefly Eng. dial.
 
FOOLED - adjectives
• EASY easily taken advantage of or imposed upon; easily fooled; credulous, gullible ..1698
fooled - peson 
• EASY MEAT someone who is easily fooled or seduced; a dupe; an easy target for deception ...L19 sl.
  
FOOLERY - nouns (also see FOOLISHNESS)
• BARNEY nonsense, foolery ...1868 Eng. dial.
• BARNEYING nonsense, foolery ...Bk1898 Eng. dial.
• BAUBLE a childish or foolish matter of affair; a piece of childish foolery ...1579
• BAUBLERY † childish foolery; trifling business ...1583
• MONKEYSHINES foolish antics; embarrassing behaviour ...1828 US sl.
• NIDGERY †* a small or worthless object; a trifle; a knickknack; a piece of foolery ...1611 
​
FOOLHARDY - adjectives
• BALLSY courageous; daring; foolhardy ...Bk2006 US sl.
• COLL-HARDY †* foolhardy; foolishly rash ...1581
• DARESOME venturesome, foolhardy ...1864 Eng. dial.
• DARING-HARDY † foolhardy, presumptuous, audacious ...1593
• FLASH conceited, foolhardy, swaggering ...Bk1892 Aust. sl.
• TEMEROUS * rash, reckless, foolhardy ...1461
• VENTURELESS venturesome, foolhardy, rash ...Bk1905 Eng. dial.
foolhardy - nouns
• MOONRAKING the act of taking part in a foolhardy or unfruitful activity
foolhardy - person
• GIBBY - a reckless, foolhardy person ...1968 US Black sl. 
foolhardy - verbs 
• DO DAGS to do something that the other person cannot do; to show off; to play foolhardy tricks ...c1850 colloq.
• HAVE BRASS BALLS to be foolhardy, over-bold ...Bk2002 Amer. sl.
• HAVE CAST-IRON BALLS to be foolhardy, over-bold ...Bk2002 Amer. sl.
• PLAY WITH THE BULL to run needless risks; to be foolhardy ...B1900 Eng. dial.
• TAKE A BEAR BY THE TOOTH to take foolhardy risks ...1719
 
FOOLING ABOUT, FOOLING AROUND - adjectives
• DALLACKING fooling, play acting ...2000 Ireland sl.
• GOOGY-GOOGY given to playing pranks; fooling around ...1960s sl.
• PROMOSSING talking rubbish, playing the fool, mooning about ...Bk1892 Aust. sl.
fooling about, fooling around - nouns 
• BUN-WORRY a jollification; a hilarious occasion; a fooling about ...L19 Aust. & NZ sl.
 
FOOLISH - adjectives
• ABDERIAN given to incessant or continued laughter; inclined to foolish or excessive merriment; foolish, silly ...18C
• ADOTED † grown silly, become foolish; infatuated ...c1230
• AIR-HEADED foolish, unintelligent; frivolous; scatterbrained ...1976 sl., orig. US
• ANSERINE stupid, foolish, silly ...1607
• ANSEROUS as stupid as a goose; silly, foolish ...1826
• APE † foolish, silly ...c1370
• ASS-BRAINED foolish; silly; witless ...Bk1942 Amer. sl.
• BABOONISH foolish ...E16
• BALD-HEADED stupid, foolish ...1884 US Black sl.
• BALL-HEADED foolish ...1884 Amer. dial.
• BARMY light-headed, foolish ...1911 Sc. & Amer. dial.
• BARMY-BRAINED foolish, giddy, flighty; light-headed ...1824 Sc.
• BARMY-FACED having a foolish or silly expression ...1724 Sc.
• BEDAFT † foolish, stupid ...1572
• BEDLAM belonging to a madhouse; mad, wild, ill-behaved, foolish ...a1535
• BEDLAMITISH mad, foolish ...1824
• BEGOYT foolish ...1787 Sc.
• BENNISH foolish ...17C sl.
• BENT AS A SCRUB TICK crazy; foolish ...Bk1999 Aust. sl.
• BESOM-HEADED weak-minded, foolish, stupid ...1864
• BIRD-BRAINED foolish, slow-witted, unintelligent, stupid ...1922 sl.
• BLATHRIE nonsensical, foolish ...Bk1911 Sc.
• BLETHER-HEADED foolish; noisy ...Bk1911 Sc.
• BONE-HEADED foolish, slow-witted, unintelligent, stupid ...1903 sl., orig. US
• BOOF-HEADED gullible; foolish; stupid ...c1930 Aust. sl.
• BUFFLE-BRAINED stupid, foolish ...1900 Amer. dial.
• BUGGY foolish, silly, witless, crazy, demented, insane, mentally deficient ...1905 Amer. dial.
• BUGS foolish, silly, crazy, demented, insane, mentally deficient ...1915 Amer. dial.
• CAKE stupid, foolish, daft ...L19 sl.
• CAKEY stupid, foolish, daft; half-witted ...L19 sl.
• CALFISH foolish ...Bk1898 Eng. dial.
• CANG † foolish, silly ...a1225
• CANGED † foolish, besotted ...a1225
• CANK † foolish, silly ...a1225
• CEMENT-HEADED stupid, foolish ...1962 Amer. sl.
• CHANG † foolish, silly ...a1225
• CHANK † foolish, silly ...a1225
• CHOOKEE foolish, cowardly ...1983 Amer. dial.
• CHUBBLE-HEADED silly, foolish ...1892 Eng. dial.
• CHUCKLE-HEADED stupid, foolish ...M18
• CLUELESS foolish, slow-witted, unintelligent, stupid ...1943 sl.
• COCK-BRAINED having little judgement; foolish and light-headed; silly, giddy, rash, harebrained, thoughtless, flighty ...1530
• COCKLE-BRAINED whimsical, eccentric, flighty, fanciful; foolish, chuckle-headed ...1824 Sc.
• CORK-BRAINED foolish; silly; witless ...Bk1942 Amer. sl.
• CORKY stupid, foolish ...2000s US Black sl.
• CORKY-BRAINED silly, foolish ...1699 sl.
• CRAZY WITH THE HEAT foolish; silly; witless ...Bk1942 Amer. sl.
• CUCKOO foolish; silly; witless; slightly mad ...Bk1942 Amer. colloq.
• DAFFADOWN DILLY silly, foolish, simple ...1950s rhyming sl.
• DAFFEY eccentric; foolish ...L19 sl.
• DAFFING playful, sportive, foolish ...1724 Sc. 
• DAFFY daft; mad; crazy; silly; amusingly eccentric; foolish ...1884 US sl.
• DAFFYDOWNDILLY (also as 'daffydown dilly') silly, foolish, simple ...1950s rhyming sl.
• DAFFY-HEADED feather-brained; foolish; daft ...1981 UK sl.
• DAFT silly, foolish, stupid ...c1325 chiefly Sc. & N. Eng. dial.
• DAFT AS PANDON YATS silly, foolish ...Bk1905 Eng. dial.
• DAFT-HEADED foolish ...Bk1900 Eng. dial.
• DAFTISH somewhat silly, foolish, or stupid; somewhat slow of intellect, in some degree deranged ...1825 Sc. & Eng. dial.
• DAFT-LIKE foolish, dull-witted, mad, absurd ... 1790 Sc. & N. Eng. dial.
• DAFTLY weak-minded, foolish ...1880 Sc.
• DAMFOOL damnably foolish; silly; stupid and irritating ...c1895 colloq.
• DAMN-FOOL damnably foolish; silly; stupid and irritating ...19C colloq.
• DAMNFOOLISH foolish; silly; witless ...Bk1942 Amer. sl.
• DAMP foolish, stupid; crazy ...L19 sl.
• DAMPHOOL damnably foolish ...19C colloq.
• DAMPHOOLISH foolish; silly; witless ...Bk1942 Amer. sl.
• DANDERING foolish, weak-minded, twaddling; incoherent, rambling in speech ...Bk1900 Eng. dial.
• DATELESS stupefied, foolish, disordered in min, having the faculties failing through age ...1685 Eng. dial.
• DAUPET silly, stupid, foolish, imbecile ...1788 Sc.
• DAWPIT silly, stupid, foolish, imbecile ...1788 Sc.
• DEDA simple, foolish, of inactive mind and body ...B1900 Eng. dial.  
• DESIPIENT * foolish, silly, childish, playful; playing the fool; idly trifling ...1727
• DILEERIOUS extremely foolish ...1891 Sc.
• DILL-BRAINED foolish ...1975 Aust. sl.
• DILLY silly, foolish ...1905 Aust. sl.
• DIM foolish, slow-witted, unintelligent, stupid ...1892 sl.
• DIM-WITTED foolish, slow-witted, unintelligent, stupid ...1940 sl.
• DING-A-LING foolish, crazy ...1959 US sl.
• DINGBATS stupid, foolish ...1950 Aust. sl.
• DINGY foolish, silly, witless, crazy; confused, mixed up ...1911 Amer. dial.
• DIPPY foolish, unstable, silly; crazy, demented ...1899 US sl.
• DIZZELL foolish; silly; witless ...Bk1942 Amer. sl.
• DIZZY of a woman: silly, foolish ...1878 Amer. dial.
• DIZZY-DOPEY foolish; silly; witless ...Bk1942 Amer. sl.
• DIZZY-HEADED of a woman: silly, foolish ...1965 Amer. dial.
• DIZZY IN THE HEAD of a woman: silly, foolish ...1965 Amer. dial.
• DODDERING shaky, feeble, or infirm, as from old age; foolish, senile ...Bk1942 colloq.
• DOOFY silly, foolish, eccentric ...1980s US sl, chiefly juvenile usage
• DOPEY foolish, slow-witted, unintelligent, stupid ...1903 sl.. orig. US
• DOPY foolish, slow-witted, unintelligent, stupid ...1903 sl., orig. US
• DOTTY foolish; silly; witless ...Bk1942 Amer. colloq.
• DOZEY foolish, slow-witted, unintelligent, stupid ...1924 Brit. sl.
• DOZY foolish, slow-witted, unintelligent, stupid ...1924 Brit. sl.
• DRONGO - foolish ...1945 Aust. sl.
• DUMB foolish, slow-witted, unintelligent, stupid ...1823 sl.
• DUMB-ASS stupid, foolish ...1957 US sl.
• DUMB-ASSED foolish, slow-witted, unintelligent, stupid ...1957 US sl.
• DUNCING † behaving like a dunce; stupid, foolish ...1584
• DUNDERHEADED stupid, foolish, slow-witted ...1692
• DUNDERING stupid, foolish; blundering ...1840
• DUNT stupefied, numbed, dazed; stupid, foolish, dizzy, muddle-headed ...1787 Eng. dial.
• DUSI † foolish, stupid ...c1175
• DWEEBY foolish, inept, out of touch with current trends ...1987 US sl.
• EGEDE † foolish ...a1225
• EMPTY-BEANED foolish; silly; witless ...Bk1942 Amer. sl.
• FARMER foolish ...M19 sl.
• FAT-BRAINED foolish, stupid ...L18 sl.
• FAT-HEADED foolish, stupid ...c1510
• FATUANT †* behaving foolishly; foolish, silly ...1641
• FATUOUS foolish, vacantly silly, stupid, besotted, infatuated ...1633
• FEATHER-BRAINED foolish, giddy, light-headed ...1820
• FEATHER-MINDED foolish; silly; witless ...Bk1942 Amer. sl.
• FEATHER-PATED foolish, giddy, light-headed, silly ...1820
• FIDDLE-BRAINED † foolish, frivolous ...B1900
• FISH foolish, stupid ...1980 Amer. dial.
• FLOCK-PATED † silly, stupid, foolish; giddy; having a head or brains like wool ...?1640
• FOLLY-FOO very foolish ...1898 Sc.
• FOND AS A BESOM very foolish; apt to commit absurd mistakes ...Bk1898 Eng. dial.
• FOOL foolish ...Bk1974 Amer. colloq.
• FOOL-HEADED foolish; silly; witless ...1914 Amer. sl.
• FOOTY foolish, simple ...19C sl.
• FOPPERLY † silly, foolish ...1599
• FURIOUS † foolish, absurd ...1526
• FUZZY foolish; silly; witless ...Bk1942 Amer. sl.
• GABY foolish, idiotic ...1874 Eng. dial.
• GAELIC foolish, ingenuous, naive ...1910 Sc.
• GAFFLED silly, foolish ...Bk1900 Eng. dial.
• GAGA foolish; silly; witless; sentimental about, infatuated ...1917 sl.
• GAIPY rash, foolish, imprudent ...1929 Sc.
• GALEERY foolish ...20C Irish sl.
• GAMALEERIE foolish ...1825 Sc.
• GAMAREERIE foolish ...1880 Sc.
• GAMMEREERIE foolish ...1880 Sc.
• GANDER-FACED foolish-looking ...L19 sl.
• GANDERISH foolish; silly; witless ...Bk1942 Amer. sl.
• GAPING-MOUTHED gaping, foolish, idiotic ...Bk1900 Eng. dial.  
• GAPPY rash, foolish, imprudent ...1929 Sc.
• GAUFFIN light-headed, foolish, thoughtless, giddy ...1810 Sc.
• GAWBY foolish, idiotic; ill-mannered, uncouth ...1874 Eng. dial.
• GEND † foolish, simple ...a1500 Sc.
• GIDDISH †* giddy, fickle, foolish ...1566
• GIGGISH lively, flighty, wanton, trifling, silly, foolish ...1523
• GLAIKET, GLAIKIT stupid, careless, foolish ...1889 Sc.
• GONNER-NOPED thoughtless, foolish ...Bk1900 Eng. dial.
• GOOFY silly, foolish ...1910s sl.
• GOOFY-ASS silly, foolish ...1910s sl.
• GOO-GOO foolish; mawkish; sentimental ...1910s US sl.
• GOOPISH foolish; silly; witless ...Bk1942 Amer. sl.
• GOOPY foolish; silly; witless ...Bk1942 Amer. sl.
• GOOSEY foolish, stupid. silly, light-headed, witless ...1919 Amer. dial.
• GORMLESS foolish, slow-witted, unintelligent, stupid ...c1746 sl.
• GUCKED † foolish, silly ...c1450 chiefly Sc.
• GUMP-HEADED stupid, foolish, awkward ...1722 Amer. dial.
• GUPPY foolish, stupid, silly ...c1930 sl.
• GYPED, GYPIT silly, foolish, idiotic ...1804 Sc.
• HAGGIS-HEADED soft-headed, foolish, stupid ...1715 Sc.
• HALF-BAKED foolish, silly, weak of intellect;  raw, inexperienced ...1897 Eng. dial.
• HALF-BAKED foolish, silly, half-witted, weak of intellect;  raw, inexperienced ...1855 Eng. dial.
• HALF-BAPTIZED foolish, silly, weak of intellect ...1795 Eng. dial.
• HALF-GONE foolish, silly, weak of intellect ...1893 Eng. dial.
• HALF RIGHT foolish, silly, weak of intellect ...1866 Eng. dial.
• HALF-ROCKED half-witted, silly, foolish, oafish ...1869 Eng. dial.
• HALF-SAVED half-witted, foolish, silly, weak of intellect ...1871 Eng. dial.
• HALF-SCRAPED foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-SHAKED foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-SHANNY foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-SHAVED foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-SOAKED foolish, silly, weak of intellect ...1895 Eng. dial.
• HALF-STRAIN foolish, silly, weak of intellect ...1873 Eng. dial.
• HALF-STRAINED foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF THERE foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-THICK foolish, silly, weak of intellect ...Bk1905 Eng. dial.
• HALF-WITTED not having all one's wits; imbecile; foolish; stupid ...1712
• HALLACHIN noisy, foolish ...Bk1905 Sc.
• HALLOPIN unsteady, unsettled, foolish ...Bk1905 Sc.
• HALOKIT giddy, thoughtless, foolish, crazy ...1724 Sc.
• HARISH † of the nature of a hare; mad, foolish ...1552
• HASK foolish; not quite right in the head ...Bk1902 Eng. dial.
• HAUVING simple-witted, foolish, clownish ...Bk1902 Eng. dial.
• HAUVISH simple-witted, foolish, clownish ...Bk1902 Eng. dial.
• HAVEREL foolish, silly, half-witted, nonsensical; talking foolishly ...1685 Sc. & N. Eng. dial.
• HAVERIL foolish, silly, nonsensical; talking foolishly ...1685 Sc. & N. Eng. dial.
• HAWKED stupid, foolish ...1790 Sc.
• HEARTLESS † without understanding; foolish ...1382
• HEN-HEADED brainless, foolish ...1700 Eng. & Amer. dial.
• HEN-MINDED brainless, flighty, capricious; foolish, silly, witless ...1892 Amer. dial.
• HOLLOW-HEADED foolish, silly ...B1900 Eng. dial.
• IDLE † void of meaning or sense; foolish, silly, incoherent ...1548
• IDLE-HEADED † of little understanding or intellect; silly, foolish; crazy ...1598
• INFIRM silly, foolish ...1890 Eng. dial.
• INSIPIENT * void of wisdom, understanding, or intellect; unwise, foolish, stupid ...1528
• IVORY-DOMED stupid, foolish ...1932 US sl.
• JINGLE-BRAINED foolish; silly; witless ...Bk1942 Amer. sl.
• KANG † foolish, silly ...a1225
• KNOCK-SOFTLY stupid, foolish ...1887 Eng. dial.
• LACK-THOUGHT wanting or lacking thought; foolish, stupid, vacant ...1829
• LACK-WIT foolish, idiotic, or simple-minded ...1735
• LAMB-BRAINED foolish ...1998 NZ sl.
• LAME-BRAINED foolish, slow-witted, unintelligent, stupid ...1929 sl., chiefly US
• LEAN-WITTED silly, stupid, foolish; having little sense or shrewdness ...1593
• LEARY dazed, bewildered; foolish, half-witted ...1911 Amer. dial.
• LEATHER-HEADED stupid, foolish, slow-witted ...a1668
• LEFT-WITTED * dull, stupid, foolish, silly ...1616
• LEWD † foolish, unskilful, bungling; ill-bred, ill-mannered ...c1380
• LOLO insane, crazy; foolish, dull, stupid ...1938 Hawaii
• LOONY foolish; silly; witless ...Bk1942 Amer. sl.
• LUNATIC madly foolish, frantic, idiotic ...1571
• LUNCH stupid, foolish, crazy ...1960s sl.
• LUNKHEADED slow-witted, foolish ...L19 sl.
• LUNY foolish; silly; witless ...Bk1942 Amer. sl.
• MAD AS A MAGGOT, AS very crazy, extremely eccentric; hence, egregiously foolish ...20C NZ sl.
• MADDED † mad, foolish ...Bk1905 Sc.
• MADDLING foolish, silly, flighty; confused ...Bk1905 Eng, dial.
• MAFFLING blundering, clumsy, foolish, stupid ...Bk1905 Eng. dial.
• MARMOSETICAL † characteristic of a marmoset; apishly foolish ...1630
• MAWMISH † foolish, silly, idle ...B1900
• MAZLING stupid, foolish, confused ...1885 Eng. dial.
• MEAT-HEADED foolish, slow-witted, unintelligent, stupid ...1949 sl., chiefly US
• MENSELESS thoughtless, silly, foolish; senseless ...1809 Sc.
• MOOKY foolish, contemptible, ineffectual ...1967 US sl.
• MOONY crazy; foolish; silly, esp. in demonstrating affection ...Bk1942 sl.
• MOPISH † foolish, silly
• MUDDLE-BRAINED confused, foolish, simple ...M18
• MUDDLE-HEADED confused, foolish, simple ...M18
• MUGGY foolish, in the manner of a mug ...1997 UK sl.
• MULLET-HEADED foolish, slow-witted, unintelligent, stupid ...1857 US sl.
• MUSH-FACED stupid, foolish ...1910s sl.
• MUTTON-HEADED foolish, slow-witted, unintelligent, stupid ...1768 sl.
• NANNY-CRATTY foolish, weak-minded, childish; of small account; generally used of persons, but also of a conversation or work ...Bk1905 Eng. dial.
• NARROW stupid, foolish ...Bk1902 sl.
• NEDDYISH silly, foolish ...Bk1905 Eng. dial.
• NENA simple, foolish ...Bk1905 Eng. dial.
• NERTS crazy, foolish ...1910s US sl.
• NERTZ crazy, foolish ...1910s US sl.
• NICKIN foolish, simple ...L17 sl.
• NIKEY foolish, simple ...L17 sl.
• NIKIN foolish, simple ...L17 sl.
• NINNY-NONNY stupid, foolish, weak-minded, childish ...Bk1865 Eng. dial.
• NIPPERTY-TIPPERTY silly, frivolous, foolish, light-headed ...1817 Sc. 
• NISEY † foolish, dull ...1709
• NIZY foolish, dull ...L17 sl.
• NIZZIE foolish, dull ...L17 sl.
• OAFING stupid, foolish ...Bk1905 Eng. dial.
• OAF-ROCK'D half-witted, stupid, foolish, silly ...Bk1905 Eng. dial.
• OFF mad, very foolish ...L19 sl.
• OFF ONE'S KADOOVA insane, foolish ...Bk1999 Aust. sl.
• OFF ONE'S NUT crazy; foolish ...Aust. sl.
• PAPER-SCULLED. foolish, simple ...L17 sl.
• PAPER-SKULLED foolish, simple ...L17 sl.
• PAPPY-SHOW foolish, ridiculous ...L19 W. Indies
• PEA-BRAINED foolish, slow-witted, unintelligent, stupid ...1950 sl.
• POPPY-SHOW foolish, ridiculous ...L19 W. Indies
• PRECIOUS FOOLISH foolish; silly; witless ...Bk1942 Amer. sl.
• PRIZE SAPPY foolish; silly; witless ...Bk1942 Amer. sl.
• PRUNY foolish; silly; witless ...Bk1942 Amer. sl.
• PUERILE childishly foolish; immature or trivial ...17C
• PUGGLED given to foolish behaviour ...1985 Sc. sl.
• PUPPY-SHOW foolish, ridiculous ...L19 W. Indies
• RADGE of an idea or situation: foolish, silly, absurd ...1961 sl.
• RADGY of an idea or situation: foolish, absurd ...1990s sl.
• RAFFLE idle; foolish ...Bk19C Eng. dial.
• RALPH weak, silly, foolish ...Bk1905 Eng. dial.
• RATTLE-BEANED foolish; silly; witless ...Bk1942 Amer. sl.
• RATTLE-BRAINED talkative; flighty; harebrained; silly; stupid; prone to confusion; foolish; unable to concentrate ...1868 Sc.
• RATTLED confused; foolish; silly; confused by excitement ...20C Amer. sl.
• RATTLE-HEADED empty-headed, stupid; foolish and noisy; talkative, chattering, giddy, flighty, hare-brained ...1647
​• ROCKED IN A STONE KITCHEN said of a fool, his brains having been disordered by the jumbling of his cradle ...1809
• SACKLESS lacking common sense; silly; foolish; stupid; thoughtless; useless, awkward ...1878 Sc. & Eng. dial.
• SAGGER-YEDDED stupid, foolish ...Bk1904 Eng. dial.
• SAKELESS without sense or gumption; silly, foolish, lacking drive or energy, sloppy, careless ...1820 Sc.
• SAMMY foolish, dull ...E19 sl.
• SANNOCKING silly, foolish ...1893 Eng. dial.
• SAP-HEAD foolish ...M17 sl.
• SAP-HEADED foolish, silly, stupid, witless ...1665
• SAPLESS foolish, silly, witless ...Bk1904 Eng. dial.
• SAPPY foolish, silly, witless ...1670
• SAPPY-HEADED simple-minded, silly, foolish ...1881
• SART foolish, imbecile, daft ...1885 Eng. dial.
• SAUFFLING foolish, weak ...Bk1904 Eng. dial.
• SAUMPY weak-minded, foolish ...1856 Eng. dial.
• SAWNEY foolish, stupid, weak; foolishly sentimental ...1894 Eng. dial.
• SCRAMBLE-BRAIN foolish; silly; witless ...Bk1942 Amer. sl.
• SCRANNY crazy, mad, distracted; simple, foolish; bewildered ...Bk1904 Eng. dial.
• SHALLOW-BRAINED † having no depth of intellect or understanding; foolish, empty-headed
• SHALLOW-PATED having no depth of intellect or understanding; foolish, empty-headed ...arch.
• SHAY-BRAINED foolish, silly ...1806 Eng. dial.
• SHORT OF NUMBERS IN THE UPPER HOUSE foolish, stupid ...Bk1999 Aust. sl.
• SICK OF THE SIMPLES foolish ...18C colloq
• SIL(L) foolish ...1930s sl.
• SILLY-ARSE stupid, foolish ...1910s sl., chiefly US
• SILLY AS A WET HEN extremely foolish, silly, or stupid ...1980s NZ sl.
• SILLY AS A WHEEL extremely foolish,  silly or stupid ...1950s Aust. sl.
• SILLY-ASS stupid, foolish ...1910s sl., chiefly US
• SILLY-ASSED stupid, foolish ...1910s sl., chiefly US
• SILLY-BORN stupid, foolish ...1940s sl.
• SILLYISH * somewhat foolish ...1761
• SIMP foolish ...2000 US sl.
• SIMPY foolish, gullible ...1940s sl.
• SLAP-HAPPY foolish; silly; witless ...Bk1942 Amer. sl.
• SLAPPY foolish; silly; witless ...Bk1942 Amer. sl.
• SLUGGY foolish; silly; witless ...Bk1942 Amer. sl.
• SLUG-NUTTY foolish; silly; witless ...Bk1942 Amer. sl.
• SNEPE * foolish, silly ...a1250
• SPOONY foolish, silly ...1805 colloq.
• SQUIRISH foolish ...L18 sl.
• STEAMBOATS foolish, silly ...2000 UK sl.
• STULTILOQUENT * talking foolishly; given to silly talk; babbling ...1845
• STULTITIOUS † foolish, ridiculous ...1547
• STULTY †* foolish, stupid ...1387-8
• TABETLESS heedless, foolish, silly ...1786 Sc.
• TACOU foolish, stupid ...20C W. Indies sl.
• TAFFEREL thoughtless, foolish, giddy; also, ill-dressed ...1822 Sc.
• TAIVERT stupid, foolish, muddle-headed, slow-witted, half-witted ...1818 Sc.
• TAKE YOUR PICK stupid, foolish ...1998 UK rhyming sl. for 'thick'
• TAPETLESS heedless, foolish, silly ...1786 Sc.
• TAPIE foolish, awkward, slovenly, foolishly thoughtless ...1706 Sc. & N. Eng. dial.
• TAUPIE foolish, awkward, slovenly, ill-conditioned; foolishly thoughtless ...1706 Sc. & N. Eng. dial.
• TAUPY foolish, awkward, slovenly, ill-conditioned; tawdry ...1823 Sc.
• TAWPIE foolish, awkward, slovenly, ill-conditioned, foolishly thoughtless; tawdry ...1706 Sc. & N. Eng. dial.
• TAWPY foolish, awkward, slovenly, ill-conditioned; tawdry ...1823 Sc.
• TEWITISH wild, foolish ...Bk1905 Eng. dial.
• THICK foolish, slow-witted, unintelligent, stupid ...a1800 sl.
• TIN-EARED foolish ...1930s sl.
• TITTERY foolish; silly; witless ...Bk1942 Amer. sl.
• TOMFOOL extremely foolish
• TUNKLE-HEADED foolish, stupid ...1903 Amer. dial.
• UNASINOUS agreeing in stupidity; displaying ignorance or foolishness by all ...1656
​• UP AGAINST THE WALL foolish, stupid ...1960s US college sl.
• VAIN † of persons: devoid of sense or wisdom; foolish, silly, thoughtless; of an idle or futile nature or disposition ...1390 rare or obs.
• VOLAGE giddy, foolish; fickle, inconstant, inconsiderate ...a1366
• VOOM-VOOM foolish; silly; witless ...Bk1942 Amer. sl.
• WANWITTY † foolish ...a1500
• WOODENTOP foolish ...1983 UK sl.
• WRONG silly, foolish; extremely eccentric, or slightly mad ...1920s Aust. sl.
• YAPPY foolish, soft; idiotic ...M19 sl.
• YAWNEY simple, foolish ...19C sl.
• ZATHY simple, foolish ...Bk1904 Eng. dial.
foolish - nouns
• IDIOTICALS foolish things; nonsense; cheap, trashy news ...1826 Sc.
• MUG'S GAME a thankless task; a useless, foolish, or unprofitable activity ...1900
foolish - verbs
• ACT THE ANGORA to behave foolishly ...Bk1999 Aust. sl.
• COME DOWN IN THE LAST SHOWER to be inexperienced, foolish, or gullible; chiefly used in negative contexts ...1883 Aust. & NZ colloq.
• HAVE BIRD DROPPINGS FOR BRAINS to be extremely stupid or foolish ...1979
• HAVE BRICKDUST FOR BRAINS to be extremely stupid or foolish ...1800
• HAVE COTTON-BATTING FOR BRAINS to be extremely stupid or foolish ...1901
• HAVE SAWDUST FOR BRAINS to be extremely stupid or foolish ...1833
• HAVE SHIT FOR BRAINS to be extremely stupid or foolish ...1960 sl., orig. US
• HAVE SOUP FOR BRAINS to be extremely stupid or foolish ...1979
• JUMP SMART to act in a foolishly 'clever' manner ...1970s US Black sl.
• MAKE AN ASS OF SOMEONE to cause someone to appear absurd or foolish ...1548
• MAKE A PROPER GALAH OF ONESELF to behave foolishly ...Bk1999 Aust. sl.
• RAIN DOWN IN THE LAST SHOWER to be inexperienced, foolish, or gullible; chiefly used in negative contexts ...1843 Aust. & NZ colloq.
• TURN A PERSON''S BRAIN to make a person dizzy or giddy; to disturb a person's mental balance, to make a person foolish or rash ...c1440
foolish - phrases 
• MORE F THAN R 'more fool than rogue'; originally and chiefly used of a servant ...M19 sl.
• YOU'RE OUT OF YOUR TINY MIND you're crazy, foolish, mad ...1970 UK sl.
 
FOOLISHLY - adverbs
• CANGLICHE † foolishly ...a1225
• DAFFY-LIKE foolishly, like an idiot ...Bk1900 Eng. dial.
• DAFTLY foolishly ...1787 Sc.
• DAWKINLY stupidly, foolishly ...1750 Eng. dial.
• GOOK-EYED stupidly, foolishly, vacantly ...1950s US sl.
• HEARTLESSLY † foolishly ...1611
• LEWDLY † ignorantly; foolishly ...c1380
• LIKE A MONKEY TRYING TO BUGGER A FOOTBALL very clumsy; foolishly ...1965 Amer. sl.
• LIKE A MONKEY TRYING TO FUCK A FOOTBALL very clumsy; foolishly ...1981 Amer. sl.
• LOOBILY foolishly ...M14
• MAZE-LIKE stupidly, foolishly; like a madman ...1866 Eng. dial.
• OAFLY foolishly, absurdly ...Bk1905 Eng. dial.
• VAINLY † foolishly, senselessly, thoughtlessly ...1588
 
FOOLISHNESS - nouns (also see FOOLERY)
• ADDLE-HEADEDNESS fatuity, foolishness, folly ...1835
• BALONUS pretentious nonsense; humbug; foolishness ...1929 Amer. sl.
• BLADRY foolishness, deception ...Bk1911 Sc.
• BLETHERIE foolishness; deception ...Bk1911 Sc.
• BLUTE a bad or foolish action ...Bk1911 Sc.
• CACA nonsense, rubbish; foolishness ...1970s US sl.
• CHAFF nonsense, humbug, foolishness, ridicule; small, unimportant things or acts ...1859 Amer. dial.
• COD-ACTING foolish behaviour ...20C sl., orig. Irish
• DAFF fun, frolic; playing the fool ...1737 Sc.
• DAFFERY † folly, foolishness, gaiety, sportiveness; thoughtlessness ...1768 Sc.
• DAFFING fooling, folly ...1535
• DAFFLIN fooling, merriment ...Bk1900 Eng. dial.
• DAFFRY † folly, foolishness; thoughtlessness ...1768 Sc.
• DAFTNESS foolishness, dullness, madness ...1552 chiefly Sc. & Eng, dial.
• DUNDERHEADISM foolishness, stupidity ...1836
• DUSILEC † foolishness; folly ...a1225
• DUSISCHIP † foolishness; folly ...a1225
• FADOODLE †* something foolish or ridiculous; nonsense; a mere nothing; a useless trifle ...a1670
• FANDANGLE stupidity, foolishness ...1940s W. Indies sl.
• FARADIDDLE nonsense, foolishness ...1944 Amer. dial.
• FATUOUSNESS besotted foolishness, stupidity, infatuation; imbecility ...1874
• FIGGLE-FAGGLE conduct which is foolish, ludicrous, or unbecoming; silly or trifling conduct; ridiculous behaviour ...19C Sc.
• FLUMMYDIDDLE foolishness, nonsense ...1903 Amer. dial.
• FOLABILITY †* foolishness, folly ...a1529 
• GOOFINESS foolishness ...1910s sl.
• GUCKRY † foolishness, folly ...1596 Sc.
• GYPERY foolish or silly behaviour ...1832 Sc.
• GYPITNESS foolishness, silliness ...1804 Sc.
• HAIVER a piece of folly or nonsense; a whim, a piece of foolishness ...1793 Sc.
• HAPPY HORSESHIT foolish stuff ...1971 US sl., esp. military usage
• HAVRELISM the habit of behaving in foolish, harum-scarum fashion ...1826 Sc.
• IDLENESS †* light-headedness, imbecility; delirium; also, folly, foolishness, silliness ...a1536
• JACKASSISM action or behaviour characteristic of a jackass or fool; foolishness, stupidity ...1817
• JACKASSNESS the quality of being a jackass or fool; foolishness, stupidity ...1803
• LALLYGAG foolishness, nonsense; idle talk, chatter ...1862 Amer. dial.
• LEATHER-HEADEDNESS stupidity; foolishness ...1879 Amer. dial.
• LEG-PULL the act of deceiving or fooling someone ...1915 Amer. sl.
• LEWDHEDE †* ignorance; want of skill, knowledge, or good-breeding; foolishness ...1401
• LEWDNESS † ignorance; want of skill, knowledge, or good-breeding; foolishness ...1362
• LOLLYGAG foolishness, nonsense; idle talk, chatter ...1862 Amer. dial.
• MAZERY nonsense, foolery; madness ...1897 Eng. dial.
• MIFF-MAFF nonsense; foolishness ...1858 Eng. dial.
• MIFKY-PIFKY foolishness or mischief, esp. of a romantic or sexual nature; sexual activity; hanky panky ...1985 Amer. jocular
• MONKEY BUSINESS foolishness; also, underhand actions or trickery; misbehaviour ...1883 Amer. sl.
• MONKEY CAPERS monkey business ...1846 Amer. sl.
• MONKEY PLAY foolishness; also, underhand actions or trickery; misbehaviour ...1953 Amer. sl.
• MONKEY-SHINES foolish behaviour ...c1832 US sl.
• MONKEY TRICKS foolish behaviour ...1653 sl.
• MONKEY WORK foolishness; also, underhand actions or trickery; misbehaviour ...1942 Amer. sl.
• MOOFKY-POOFKY foolishness or mischief, esp. of a romantic or sexual nature; sexual activity; hanky panky ...1994 Amer. jocular
• MOOFTY-POOFTY foolishness or mischief, esp. of a romantic or sexual nature; sexual activity; hanky panky ...1996 Amer. jocular
• MOONSHINE foolish talk or thought
• NODDARY †* a foolish action, foolishness ...1647
• NOISE nonsensical talk; hence, foolishness ...1871 Amer. sl.
• OKEY-DOKE foolishness; stupidity; pretense ...1969 sl., esp. Black usage
• PAPPY SHOW foolishness, showing off ...L19 W. Indies
• POPPY SHOW foolishness, showing off; one who makes a stupid exhibition of themselves ...L19 W. Indies
• PUERILITY the state or quality of being a child; the quality of being childish, foolish, or trivial ...1425
• PUPPY SHOW foolishness, showing off; one who makes a stupid exhibition of themselves ...L19 W. Indies
• RAFF idle ways; foolishness ...Bk19C Eng. dial.
• RAGE † madness, folly, rashness; an instance of this; a foolish act ...a1300
• SAPHEADISM foolishness ...L18 sl.
• SAPPINESS foolishness, folly ...Bk1914 colloq.
• SCHMOOFKY-FOOFKY foolishness or mischief, esp. of a romantic or sexual nature; sexual activity; hanky panky ...1997 Amer. jocular
• SIMPLES † foolish or silly behaviour or conduct; foolishness, folly ...1648 obs. exc. Eng. dial.
• SIMPLESSE † deficiency in knowledge or learning; ignorance; also, lack of mental acuteness, intellectual weakness, foolishness ...c1400 obs. exc. arch.
• SOTTERY † a piece of foolishness or folly ...1598
• THING-A-ME-TOY a foolish act ...B1900 Eng. dial.
• TRUCK nonsense, foolishness ...1913 Amer. dial.
• VAINNESS † foolishness; stupidity ...1591
• VANITY † the quality of being foolish or of holding erroneous opinions ...c1386
• WANWIT † lack of wit, foolishness ...a1400 chiefly Sc.
• WOOBLES feeblemindedness, foolishness, idiocy ...1933 Amer. dial.
• YORNEYISHNESS simplicity, foolishness, half-wittedness ...1885 Eng. dial.
• YORNEYISM simplicity, foolishness, half-wittedness ...1884 Eng. dial. 
foolishness - verbs
• COME OFF THE GRASS to stop talking foolishness ...a1891 US sl.
foolishness - phrases 
• BORE FOR THE SIMPLES refers to a stupid person; the idea is that a hole in the skull might let some of the foolishness out ...1916 Amer. dial.