Green’s Dictionary of Slang

1. an attractive woman, esp. when seen as a sex object.

1936		‘Agric. College Sl. in S. Dakota’ AS XI:3 280/1: Ginch Any girl.
1950		Goldin et al. DAUL 81/1: Ginch. (’A piece of ginch’) 1. Prostitutes; loose women.
1960		Taunton Courier 23 July 3/6: American slang [...] I dream of a not too hinkty ginch [...] But no geets, no zooly.
1968		T. Wolfe Electric Kool-Aid Acid Test (1969) 112: The unquenchable Hagen of the Screw Shack prowls the Stampede for ginch ahoof.
1970		(con. 1950s) H. Junker ‘The Fifties’ in Eisen Age of Rock 2 (1970) 102: But mostly the eternal search for a little [...] ginch.
1989		(con. 1960) P. Theroux My Secret Hist. (1990) 177: Just stay here until it gets dark. Then get some ginch.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 154: They’re gonna burn for that Mexican ginch.
1992		C. Nova Trombone (2002) 31: I guess Dean Gollancz has got himself another piece of ginch somewhere. Sounds like she’s left him flat, too.
2010		J. Ellroy Hilliker Curse 13: A friend knew a ginch named Jean Feese.

2. the vagina; thus the act of sexual intercourse.

1950		Goldin et al. DAUL 81/1: Ginch. (’A piece of ginch’) [...] 2. The act of sexual intercourse.
1977		J. Olsen Secret of Fire Five 43: Plummer’s specialty is ginch, not food. ‘One of the department’s finest hosemen,’ his F.D. biography says.

3. (gay) an attractive young man.

1950		Goldin et al. DAUL 81/1: Ginch. (’A piece of ginch’) [...] passive pederasts; fags.
1972		B. Rodgers Queens’ Vernacular 161: sexually oppressed, constantly raped victim; usually straight [...] ginch (rare).
1979		Maledicta III:2 232: He also may or may not know the following words and expressions: [...] ginch.