Green’s Dictionary of Slang

1. (US) a male homosexual [queer n. (6)].

1965		Guild Dict. Homosexual Terms 38: q. cards (n.): Gay (homosexual) calling cards; usually with the addition of symbols or phrases below the name. As distinguished from gay notepaper.
1967–8		Baker et al. CUSS.
1972		B. Rodgers Queens’ Vernacular.
1989		Kirk & Madsen After The Ball 258: ‘Q-types’ – homosexuals on display. Q’s don’t wish to be seen as straight.

2. (UK drugs) a quarter ounce of a given drug.

1997		N. Barlay Curvy Lovebox 45: How many was you wantin’? Ten . . . and a q.
2002		Guardian 11 July 6: The police are not going to lift you at a party for having a half Q [eighth of an ounce] just now, so what difference will this make?
2015		67 ‘Hashtag’ 🎵 Tryna get Ps from Qs and Os.
2020		G. Krauze What They Was 13: We can buy a draw or two [...] or maybe a q [and] get properly faded.