clean-up, n. — Green’s Dictionary of Slang

clean-up n.

1. (US gambling) the climactic round of a gambling game in which the successful gambler takes the last of his opponent’s money, esp. in cheating contexts.

1914		Ade ‘The New Fable of the Aerial Performer’ in Ade’s Fables 203: On the Clean-up she received enough to put her through the School.
1938		(con. 1830s) H. Asbury Sucker’s Progress 208: At length one of the ‘planters’ dealt Bowie a hand which any Poker player would bet as long as he could see, and which Bowie recognized as being intended for the big cleanup.

2. (orig. US) a profit, an exceptional financial success; a betting coup.

1878		F.H. Hart Sazerac Lying Club 21: At the same time make a nice little clean-up for himself.
1901		Boy’s Own Paper 1 June 546: We’ll have to give him a share of the clean-up in the spring.
1907		B. Fisher A. Mutt in Blackbeard Compilation (1977) 4: Mr. A. Mutt Makes a Clean-Up. He Had $25 Both Ways on Sugarmaid.
1915		Van Loan ‘Sporting Doctor’ in Taking the Count 33: You’re going to make a clean-up in the betting.
1925		Dos Passos Manhattan Transfer 29: Now it’s up to us to get in on the next great clean-up.
1933		W.R. Burnett Dark Hazard (1934) 150: ‘What’s hot?’ [...] ‘Tulsa Flier. I know the guy that owns him. It’s a clean-up.’.
1966		J. Holledge Great Aust. Gamble 17: [H]is successful £200,000 plunge on Purser in the 1924 Caulfield Cup [...] was reputed to be the biggest single turf clean-up Australia has known.
1986		C. Hiaasen Tourist Season (1987) 188: Two weeks is a long time without your clean-up hitter.

3. (US prison) a story used to avoid a difficult situation, an alibi.

1971–2

C. Shafer ‘Catheads [...] and Cho-Cho Sticks’ in Abernethy Bounty of Texas (1990) 201: clean up, n. – a story used to get out of a good or a bad situation: ‘You need a good clean up for an alibi.’.

4. (US) an excuse, a justification, a way of extricating oneself from a situation.

2001

(con. 1975–6) E. Little Steel Toes 90: Planning to hit that drugstore was an inexcusable stupidity, there’s no cleanup for something like that.