Defeat with cunning (6)
I believe the answer is:
outfox
'defeat with cunning' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for outfox that I've seen before include "Be too clever for, like Reynard (6)" , "Be too clever for, in vulpine mode" , "Surpass in art" , "Beat by cunning" , "Cunningly get the better of" .)