Green’s Dictionary of Slang

1. difficult, troublesome.

1750		Love at First Sight 185: [I]f they [i.e. apothecaries’ boys] continue their Monkey Meetings, and longer infest the Town with their mischievous Tricks [...] the Pump or Ducking-Pond will certainly be their Lot.
1977		(con. 1950s) Nicholson & Smith Spend, Spend, Spend (1978) 55: Matt’s mother would untidy it [...] Then If I told her off she’d get really monkey about it.
1999		Guardian Guide 22–28 May 6: You and your monkey friends are ruining it for everybody else.

2. (US) a general derog., esp. in racist contexts.

1842		Whip & Satirist of NY & Brooklyn (NY) 18 June n.p.: These monkey Frenchmen.
1904		‘O. Henry’ Cabbages & Kings 201: [of Central America] ‘We struck the monkey coast one afternoon [...] The monkeys were loading her up with big barges’.
1926		E. Walrond Tropic Death (1972) 64: Hey, Porto Rico, snap into it! Dis ain’t no time to get foolin’ wit’ no monkey jane.
1929		C. McKay Banjo 125: ‘I’ll tell you a real man story, pardner,’ said Banjo, ‘that ain’t no monkey-coon affair.’.
1939		J. Cary Mister Johnson (1952) 123: I know the law as well as you do, Mr. Monkeybrand.
1952		B. Appel Plunder (2005) 261: The Red bastids [...] that’s what they want now – a goddam monkey revolution. [Ibid.] 303: A light voice questioned him in Tagalog. Monkey talk, he thought.
1968		Champion Jack Dupree & Mickey Baker ‘I’m Tired of Moanin’’ 🎵 Well I’m leaving heeeee, swear I can’t take you / ’Cause there’s nothing now baby, a monkey woman like you can do.
1991		Cooper & Wright New Jack City [film script] He’s kicking his monkey ass.
1994		N. McCall Makes Me Wanna Holler (1995) 303: Should I straighten his monkey ass here and now.

3. corrupt, illicit.

1974

G.F. Newman You Flash Bastard 159: Sneed had another bent account in Pall Mall which no-one knew about. He had opened it with forged references from two monkey addresses, and all the transactions had been by cash.