Green’s Dictionary of Slang

1. (usu. drugs) pure, unadulterated.

1930		J. Lait Put on the Spot 111: He walked into the bar and motioned for whisky. Bandy Gluntz, the vassal in charge, opened a little cabinet and drew forth a bottle of the uncut stuff.
1959		W. Burroughs Naked Lunch (1968) 143: This is pure uncut boy in the street.
1966		T. Keyes All Night Stand 122: Even if you got it straight from the boat I wouldn’t believe you got uncut gear like this.
1971		E.E. Landy Underground Dict. (1972).
1980		E. Folb Runnin’ Down Some Lines 259: uncut Undiluted (as in drugs or marijuana).
1993		K. Scott Monster (1994) 295: Fat Rat, like me, was uncut street.
2000		M. Manning Get Your Cock Out 35: Mincey had just hoovered up another half teaspoon of uncut Charlie.

2. (US gay, also u.c.) uncircumcised.

1967		‘Philip Barrows’ Whores, Queers & Others I [ebook] He was uncut and not too big.
1978		L. Kramer Faggots 62: His wonderful uncut wop cock that deserved better things.
1987		personal ad, adult bookstore Murray & Murrell Lang. Sadomasochism (1989) 140: Male [...] U/C, seeks pleasurable encounters with TVs.
1989		Kirk & Madsen After The Ball 304: Uncut cheesy meat.
1999		Gaymart.com Queer Sl. in the Gay 90s 🌐 Uncut – Uncircumcised.
2003		K. Cage Gayle.
2010		M. Salvatore Betwen Boyfriends 292: I clicked on the attached photo: it was a close-up of his suckalicious, maybe-more-than-ten-inch, uncut dick.