causing irritation; irritating ...a1656 rare
from irritate (vb. to stir up, to excite, to provoke, to provoke, or to rouse to some action) + - ory
FIRST DOCUMENTED USE
a1656 - see EXAMPLE below
"...The other peradventure is sufficiently Grounded for Principles of Faith, yet is Weak, by reason either of some Passion, or of some irritatory and troublesome Humour in his behaviour..."
From: Golden Remains, of the Ever Memorable, Mr. John Hales, of Eaton Colledge, &c.
- John Hales