t.n.t., n.² — Green’s Dictionary of Slang

t.n.t. n.²

[SE TNT, trinitrotoluene]

1. (US black) anyone or anything that is metaphorically ‘dynamite’, wonderful, exceptional etc.

1962		S. Longstreet Flesh Peddlers (1964) 178: T.N.T., Solly – and Hulie Grimes music. Solid hits.
1983		R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].

2. in drug uses.

(a) heroin.

1977		S.N. Pradhan Drug Abuse.
2001		ONDCP Street Terms 21: T.N.T. — Heroin.

(b) fentanyl.

2001

ONDCP Street Terms 21: T.N.T. — [...] fentanyl.