Most off-the-wall (7)
I believe the answer is:
zaniest
'most off-the-wall' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for zaniest that I've seen before include "Most wacky" , "Most crazy" , "[OPPOSITE OF] most normal" , "Bananas, more than anything" , "Most crackers" .)