Green’s Dictionary of Slang

1. (US campus) an unpleasant or unpopular person.

1969

Current Sl. III:4.

2. anyone who takes drugs to excess.

1975		L. Dills CB Slanguage 125: Zonker: drug.
1975		G. Underwood ‘Razorback Sl.’ in AS L:1/2 69: zonker n One who smokes marijuana or takes drugs.