Green’s Dictionary of Slang

dumptruck n.¹

1. a car full of lesbians.

1970

J.P. Stanley ‘Homosexual Sl.’ in AS XLV:1/2 57: dump truck n Car full of lesbians (male use only).

2. a masculine lesbian.

1972

B. Rodgers Queens’ Vernacular 71: dump truck (les sl, fr pros sl dump = to beat) 1. the masculine-type lesbian who wins arguments with muscle instead of wit 2. (camp) a wrestler of either sex 3. (camp) an effeminate who is more growl than bite.

SE in slang uses

In compounds

dumptruck date (n.)

(US campus) an overweight woman.

1987		Eble Campus Sl. Oct.
1996		Eble Sl. and Sociability 71: Dumptruck date, ‘overweight female’.