Green’s Dictionary of Slang

1. to lend money at extortionate rates of interest; thus shylocking n.

1901		Sydney Sportsman (Surry Hills, NSW) 7 Aug. 1/2: Their ‘kind kerristian’ principles [...] are not averse to sweating, dishonest money-mongering, scurvy Shylocking [...] and such like ‘unco guid’ practices.
1952		(con. 1920s) ‘Harry Grey’ Hoods (1953) 246: We do shylocking, and a little booking there – horses and numbers.
1955		(con. 1934) H. Robbins A Stone for Danny Fisher 135: Fields was the big man in the neighbourhood. Politics, gambling, shylocking – the works.
1979		P. Hamill Deadly Piece 70: The cops think he’s been working with the Cubans in coke, shylocking and fencing, out in Brooklyn.
1986		N.Y. Times 30 Apr. n.p.: Gotti had been involved in illegal activities, including gambling and shylocking [R].
1987		(con. 1970s) J. Pistone Donnie Brasco (2006) 311: I’m pleased with how you’re conducting yourself [...] what you’re doing, the book, the shylocking.
1989		(con. 1930s) Courtwright & Des Jarlais Addicts Who Survived 100: I did a bit of shylocking, too, in them days. Dewey sent me away for shylocking.
2000		G.V. Higgins At End of Day (2001) 165: If you book a bet or shylock a loan, it’s still against the law.
2006		D. Winslow Winter of Frankie Machine (2007) 115: ‘They’ probably didn’t want Bap killing people, hijacking trucks, shylocking money, and running gambling operations.
2010		L. Berney Gutshot Straight [ebook] His real business was drugs, shylocking, extortion, [...] sex slaves.
2017		D. Winslow The Force [ebook] They’re into construction rackets, unions, shylocking, gambling.

2. to offer ‘protection’.

1975

E. Torres Carlito’s Way 26: I’m gonna shylock this joint, I am in — starting next week you’re turning over to me.