Green’s Dictionary of Slang

1. a liquor store.

1970		Current Sl. V:2.
1980		E. Folb Runnin’ Down Some Lines 2: Let’s trip down to the L.I.Q. and get us some pluck.

2. liquor, alcohol.

1980

E. Folb Runnin’ Down Some Lines 244: L.I.Q. Abbreviation for [...] liquor.