Green’s Dictionary of Slang

1. (orig. US) a prostitute.

1926		Variety 1 May n.p.: [headline] Mae West [...] ‘The Babe Ruth of the Stage ‘Prosties’ — New Show Realistic.
1948		K. Williams Diaries 8 Dec. 35: Had supper with him after at the Corner House — it was full of queers and prosts.
1951		Green & Laurie Show Biz from Vaude to Video 571: Prostie – prostitute. Variety’s sensitized way of describing female characters comparable to those in early Mae West plays.
1971		R.D. Pharr S.R.O. (1998) 261: ‘Every little prostie in this place has a soft spot in her granite heart for College Joe’.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 105: What about a male prostie named Bobby Inge.
1999		J. Ridley Everybody Smokes in Hell 212: Strip rollers [...] heading for the video poker at the bar to pick up a prostie who serviced at downtown prices.
2002		J. Ellroy ‘The D.A.’ in Destination: Morgue! (2004) 146: Bent cops running prosties.
2023		(con. 1962) J. Ellroy Enchanters 98: They’re inevitably hustlers, prosties, callgirls [...] hustling the L.A. film fork for all they can get.

2. (US juv.) a term of abuse.

1987

G.A. Fine With the Boys 170: Whore, n. Disliked or ugly girl (also ‘prostie’).