Green’s Dictionary of Slang

1. (gay) a potential client for a male or female street prostitute.

1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1948		Dan Burley ‘Back Door Stuff’ 6 Nov. [synd. col.] This goes for those who bring ‘prospects’ or known ‘trade’ from Brooklyn, Long Island, Staten Island and in particular Mississippi, Georgia [etc].

2. (orig. US, also P, prospector, prozzie, a recruit to a biker or prison gang before any initiation rites; also used in N.Z. prison) of new prison officers.

1991		B. Payne Staunch 76: Prospects have a hard time of it in jail. They are expected to clean out patch member’ cells, fight who and when they are told to, stand over other, usually weaker, inmates for drugs, chocs, and other booty, which they must then hand straight to the patch member, and generally act as the serrated edge for most underhand gang activity inside.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 133/1: P n. 1 = prospect sense 1. 2 = prospect sense 2 [...] 146/2: prospect n. 1 a junior member of a gang working to earn his gang patch 2 a new prison officer undergoing or recently completed his or her training [...] 147/2: prospector n. 1 = prospect sense 1 2 an inmate who acts as a servant or drudge for another inmate, carrying out menial tasks [...] 148/1: prozzie n. = prospect sense 1.
2003		McGill Reed Dict. of N.Z. Sl. 154: patch Gang insignia sewn onto jacket. [...] a patched member is distinguished from a ‘prospect’ who is still earning his patch, and any member is subject to depatch, to lose, membership. [Ibid.] 163: prospect Trainee for a ‘black’ or Maori or Polynesian gang, a prospective member.
2021		S.A. Crosby Razorblade Tears 63: ‘Just go get the fucking prospects’.

3. (gay) one who may prove a fellow homosexual.

1965		Guild Dict. Homosexual Terms 37: prospect (n.): One who will (or seems likely to) allow homosexual sex.
1972		B. Rodgers Queens’ Vernacular 159: prospect likely candidate ‘It’s funny, dear, but do you think something is wrong? My prospects never turn out to be tricks’.

4. a suspect.

1974

G.F. Newman You Flash Bastard 106: The man was a prospect who didn’t as yet add up for Sneed: walking into a bank with a gun was heavy stuff, and he’d have thought a couple of poofs would have been able to come up with something more gentle for their earner.