off-colour, adj. — Green’s Dictionary of Slang

off-colour adj.

[SE off-colour, unwell]

(US Und.) homosexual.

1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1952		Lait & Mortimer USA Confidential 51: Its off-color graduates include that star, Alger Hiss.
1965		Guild Dict. Homosexual Terms 33: off-color (adj.): Homosexual. (Criminal slang.).
1972		B. Rodgers Queens’ Vernacular.