Green’s Dictionary of Slang

effeminate; homosexual.

1924		G. Henderson Keys to Crookdom 412: Nance walk – walk like a woman.
1934		‘J.M. Hall’ Anecdota Americana II 6: As this same fag proceeded down the street he was accosted by another member of the nance fraternity.
1948		H. McCoy Kiss Tomorrow Goodbye in Four Novels (1983) 124: That club-footed nance son-of-a-bitch, he didn’t even tip me off the plainclothes men were coming.
1965		Guild Dict. Homosexual Terms 32: nance (or nancy) (n., adj.): (1) Homosexual, as used by the heterosexual. (2) Very feminine male homosexual, as used by the homosexual.
1972		B. Rodgers Queens’ Vernacular 140: nance (Brit) effeminate.