swim, n. — Green’s Dictionary of Slang

swim n.

[SE swim, a section of river well stocked with fish]

a scheme, a plan; thus a good swim, a spell of good luck.

1851		Era 10 Aug. 4/2: Onslow, in [...] Hawley’s carriage, seemed to say, ‘Looke at me, I’m in a good swim now’.
1858		A. Mayhew Paved with Gold 279: When three chaps are in the same swim, they ought to be accommodating.
1860		Hotten Dict. of Modern Sl. etc. 233: swim ‘a good swim,’ a good run of luck, a long time out of the policeman’s clutches. ? Thieves’ term.
1873		J. Greenwood In Strange Company 80: Amongst themselves they are ‘skinners,’ ‘knock-outs,’ and ‘odd-trick men,’ and they work together in what the elegant language of their profession calls a ‘swim’.
1883		E.J. Milliken Childe Chappie’s Pilgrimage 55: It’s just the same old swim, you see.
1895		Crowe Aus. Sl. Dict. 83: Swim, a‘good swim’; a long time out of the clutches of the police.
1900		A.H. Lewis ‘Mulberry Mary’ in Sandburrs 10: Mary don’t last in the Chink swim more n’ a year before there’s bats in her belfry.

go for a swim (v.)

1. (US black) to have sexual intercourse [the lubricated vagina].

1992

UGK ‘Something Good’ 🎵 The women don’t like you [...] / That’s why your little jimmy never went for a swim.

2. (US) to die by deliberate drowning .

2020

(con. 1991-94) W. Boyle City of Margins 14: A kneecapping’s the beginning. Then both arms get busted. Then, it comes to it, the guy goes for a swim.