Green’s Dictionary of Slang

1. to decriminalize money (occas. other criminal loot) that has been gained through criminal activities by ‘washing’ it through a legitimate business such as a casino or bank; thus laundry n.; launderer n .

1973		Bernstein & Woodward All the President’s Men 54: ‘It’s called ‘laundering,’’ Dardis began. ‘You set up a money chain that makes it impossible to trace the source. The Mafia does it all the time’.
1978		P. Hamill Dirty Laundry 139: You mean you were running a laundry [...] A place where mob guys bring skimmed money from Vegas, or gambling money, or dope money, any kind of money made illegally. They bring it to a bank, deposit it, leave it for a while, and then make withdrawals in nice fresh bills.
1985		N. Pileggi Wiseguy (2001) 192: He was supposed to have laundered huge amounts of money.
1986		F. Taylor Auf Wiedersehen Pet Two 233: The Scotsman had been trading as ‘Mr Clean’, ready to launder the out-and-out villains’ possessions – for a price.
1989		C. Hiaasen Skin Tight 267: A tribute to the anonymous genius of Latin American money launderers.
1997		L. Pettiway Workin’ It 71: It was a place really for laundering money for the Mafia.
1999		Observer 18 July 1: A target for drug traffickers and money launderers.
1999		P. Temple Black Tide (2012) [ebook] They call him Mr Omo. [...] He launders money for drug dealers.
2000		Guardian 23 Mar. 8: The millions of pounds the gang made were laundered through a network of companies.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 104: Joe invested 49 million dollars. It was laundered. It was lent. It suborned politicians.
2007		L. Redhead Cherry Pie [ebook] ‘Rochelle’s laundering money for Don Davison’.
2009		(con. 1960s) J. Ellroy Blood’s a Rover 21: We can launder it and funnel it into a slush fund to build those hotel-casinos.
2012		L. Berney Whiplash River [ebook] ‘To launder his money,’ Shake said. Mahmoud looked blank. ‘Wash it. Make it clean’.
2020		D. Whish-Wilson Shore Leave 28: The business was used to launder Saffron’s money.
2023		A. Nette Orphan Road 39: ‘Dad agreed to help Bennett stash the diamonds until the heat was off, then launder them’.

2. (US) to provide someone working undercover with a false identity.

1974

E.H. Hunt Undercover 129: Central Cover laundered me, i.e., a new name and consonant documentation, and assigned me a safehouse in Coconut Grove.