Based on the fantastic
Loony Tune cartoons of the 1940's & '50's that featured Bugs Bunny,
Daffy Duck, and a host of other memorable cartoon characters, many featuring the truly
schizoid voices of Mel Blank. Thus a
loony tune is a take-off on these cartoon characters - meaning a person's out of touch in a loopy, goofy, sarcastic kind of way - flaky but right on too.
"Did you see Bruno at the party last night?"
"I saw him. Since he started that smack thing, guy's a fucking
loony tune. Dive off the third-floor motel balcony into the pool & split the take for someone passing the hat or taking bets."
"Bruno, man. I saw him fold a
coat hanger & put it in his fucking mouth in 60 seconds. Forty bucks take home,
tax free.
Loony tune, man. Tres unstable."