monkey
Preserved but no longer current.
Spirit or ill temper; "to get one’s MONKEY up," to rouse his passion. A man is said to have his MONKEY up or the MONKEY on his back, when he is "riled," or out of temper; this is old, and was probably in allusion originally to the evil spirit which was supposed to be always present with a man; also under similar circumstances a man is said to have his back or hump up.
Era: ca. 1874 (Victorian)
Sources & notes
Historical definition reproduced from Hotten’s The Slang Dictionary (1874, public domain; Project Gutenberg #42108, retrieved 2026-07-31). Reflects the attitudes of its era.
Common questions
What does “monkey” mean?
Spirit or ill temper; "to get one’s MONKEY up," to rouse his passion. A man is said to have his MONKEY up or the MONKEY on his back, when he is "riled," or out of temper; this is old, and was probably in allusion originally to the evil spirit which was supposed to be always present with a man; also under similar circumstances a man is said to have his back or hump up.
Is “monkey” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.