Green’s Dictionary of Slang

tic n.²

[misreading of THC, i.e. tetrahydrocannabinol; like tac n. or tic-tac]

(drugs) phencyclidine.

1979		H. Feldman et al. Angel Dust 171: I was high on tic. It was good.
2001		ONDCP Street Terms 21: Tic — PCP in powder form.