Puzzle no more (7)
I believe the answer is:
'puzzle' is the definition.
(I know that puzzle can be written as nonplus)
'no more?' is the wordplay.
'no' becomes 'non' (I've seen this in other clues).
'more?' becomes 'plus' (I've seen this before).
(Other definitions for nonplus that I've seen before include "Surprise and confuse" , "Utterly confuse" , "stump" , "Flummox" , "Cause dismay" .)