Green’s Dictionary of Slang

1. a bribe, a sum of money that would supposedly purchase ‘a drink’ but is usu. much larger.

1970		‘Metropolitan Police Sl.’ in P. Laurie Scotland Yard (1972) 322: drink, a: a bribe.
1977		D. Powis Signs of Crime 181: Drink Euphemism for blackmail payment or a money bribe. ‘There’s a drink in it for you’ may mean there will be such payments.
1986		R.G. Barrett Real Thing 11: He slid the two fat envelopes across the desk. ‘There’s a nice drink there and there’ll be another one [...] when all this is settled.’.
1989		J. Morton Lowspeak 52: Drink [...] Probably up to about £25, as opposed to a big drink which starts in the hundreds.
1999		J. Cameron Brown Bread in Wengen [ebook] ‘He reckoned he wanted a problem sorted. Could’ve been a drink in it for you Nicky. Maybe a big drink’.
2001		K. Sampson Outlaws (ms.) 133: He does get a good drink for his services, to be fair. He’ll get thirty large out of this.
2002		J. Cameron Hell on Hoe Street 114: ‘Bung you a fuckin’ drink you meaning?’ ‘I am liking Swiss francs very much.’.
2010		‘A-Z of South African lingo’ in IOL News (Western Cape) 3 June. 🌐 C for Cooldrink: A chilled soda or a euphenism for a bribe. eg ‘If you buy me cooldrink, I’ll forget about that speeding fine.’.
2013		K. Sampson Killing Pool 66: We give him a drink and he’ll carve the bread however we want.

2. a tip, a commission, a bonus.

1986		Punch July 9: [...] there would be a nice drink in it for everybody ? The facts in the current constitutional scandal are plain.
1989		in G. Tremlett Little Legs 115: Charlie [...] might just take a drink out of it.
1999		Guardian Sport 12 Feb. 16: Give Marco a ring, could be a nice little drink in it.
2004		R.G. Barrett Rosa Marie’s Baby (2013) [ebook] ‘I want him shortened up [...] There’ll be a drink in it for you’.
2011		J.J. Connolly Viva La Madness 366: Oh, and Curtis wanted a drink outta it.
2012		(con. 1978) M. Read Chopper Unchopped n.p.: I only enter into these things every now and [...] nine times out of ten there is a good drink (payment) in it for me.
2020		G. Krauze What They Was 274: Stranger says I just want a drink [...] a little cut of what they pay me.