made or done with much labour or effort; laborious, industrious, busy; painstaking, tedious; toilsome ...a1538 obs.
from Latin operōsus (involving much effort, laborious, industrious, painstaking), from oper- , opus (work) + -ōsus
FIRST DOCUMENTED USE
a1538 - see EXAMPLE below
"...Muche Scripture recordeth this office not prophane,
If they be wrought in fayth they be good works no doubt,
These shuld be always operous mens nedes to sustaine,
And not inprōpt, but assiduous their works to bring about..."
From: The Fall and Euill Successe of Rebellion from time to time wherein is contained matter, moste meete for all estates to vewe. Written in Old Englishe verse
- Wilfrid Holme