Green’s Dictionary of Slang

1. a share of profits, of loot, of the proceeds of a robbery etc.

1872		Sportsman (London) ‘Notes on News’ 3 Feb. 4/1: [C]ircumstances in which ordinary mortals would like to have a ‘cut in’.
1883		Referee 17 June 7/4: I am anxious to have a cut in and get a big advertisement for nothing [F&H].
1895		‘’Arry on the Season’ in Punch 22 June 298/1: Wy ’Arry must ’ave a cut in.
1895		Truth (Sydney) 5 May 4/8: The local silversmith to whom I piloted the job had a great cut-in on his own account.
1900		‘The Wayback Family’ in Sun. Times (Sydney) 30 Dec. 5/3: Australia’s rorty [...] standin’ up on her hind legs with her coat off, an’ means ter have er cut in at ther first scrap handy!
1915		F. Garrett diary 14 Dec. 🌐 At teatime some generous friends of mine let me have a cut in at a tin of salmon.
1916		J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 177: An’ you gits whatever your cut-in is on his two bits.
1930		R. Whitfield ‘Murder in the Ring’ in Black Mask Stories (2010) 358/1: She figures Hurry should have a slice of the Giant. Forty percent cut-in.
1938		J. Weidman I Can Get It For You Wholesale 131: We’ve each got a cut-in on the profits.
1940		W.R. Burnett High Sierra in Four Novels (1984) 402: I’m strictly petty larceny with a cheap cut-in.

2. an interruption.

1917

R. Lardner ‘The Water Cure’ in Gullible’s Travels 164: ‘They’re worse than plays, the most o’ them,’ was the Wife’s cut-in.

3. the preliminary stage of a confidence trick when the confidence man befriends a potential victim and unveils his fraudulent scheme.

1979

‘Iceberg Slim’ Airtight Willie and Me 16: I watched Willie’s [...] choppers flashing as he pitched the ‘cut in’.