(also wacked-out or wacko or whacked or whacked-out) Crazy; eccentric; nutty: You think I'm going wacky?/ annually collects whacky accidents/ the most wacked-out cop game anybody had ever seen any cops play/ the wacked-out hustler who talks Winkler into running a call-girl service out of the morgue/ She tried to convert me to her religion! She was whacked
[1935+; fr British dialect whacky, ''fool,'' attested fr the early 1900s; whacky, ''a person who fools around,'' is attested in British tailors' talk fr the late 1800s; perhaps fr being whacked over the head too often; perhaps influenced by whack off ''masturbate,'' and semantically akin to jerk]