What is the origin of the idiom 'off-the-wall'?

Answer 1

The Phrase "OFF THE WALL"? The Phrase "Off The Wall" Where did it come from? In 1972 I was living in Chicago, walking down Garfield Boulevard with a close friend from Gary Indiana. I asked him a trick question. Then, I asked him; Do you know where I am coming from? He answered yes, but he really didn't. That's when I answered him "Off The Wall." Meaning "crazy, foolish, tricky, joking, or nonsensical. The phase exploded and caught on like fire. He took the phrase back to Gary Indiana with him. That's probably where Michael Jackson got it from. Now that's the honest truth. We still get a blast out of seeing how the phase has evolved over the years. America Vincent Caver

Answer 2

Off-the-wall: shocking, very unusual Origin: In certain sports such as handball and racketball, a player hits a ball against the wall. When it comes off the wall, one has no idea where it is going. Therefore, out of this, this expression implied, unpredictability.