vonce, n. — Green’s Dictionary of Slang

vonce n.

1. (US black/jazz) marijuana [Yid. vonce, a bedbug, thus = roach n. (2)].

1959

Esquire Nov. 70H: vonce: marijuana.

2. (US) a term of abuse [? abbr. of schwantz n. (1)].

1968

K. Brasselle Cannibals 364: That little vonce upstairs is driving me nuts.

do the vonce (v.)

(US black/jazz) to have sexual intercourse.

1959

Esquire Nov. 70H: do the vonce: make love.