Green’s Dictionary of Slang

(US) gonorrhoea.

1935		McCleary & Anderson Not For Heaven 194: ‘Have any of you guys ever had the syph?’ Cotton Sack said. ‘I’ve had the gon.’.
1963		V. Packer Alone at Night 72: In charge of syph and gon [HDAS].
1972		B. Rodgers Queens’ Vernacular 205: case of gonorrhea [...] gonny.
2003		K. Cage Gayle 73/1: Gonnie n. gonorrhoea.