Unorthodox, like Humpty-Dumpty's end? (3,3,4)
I believe the answer is:
off the wall
'unorthodox' is the definition.
I don't understand the rest of the clue.
(Other definitions for off the wall that I've seen before include "Grossly unconventional" , "American eccentric" , "how Humpty Dumpty ended up" , "Left field" , "description of peeling plaster?" .)