Fighter did me with leg moves (12)
I believe the answer is:
middleweight
'fighter' is the definition.
(I know that middleweight is a type of fighter)
'did me with leg moves' is the wordplay.
'moves' is an anagram indicator.
'did'+'me'+'with'+'leg'='didmewithleg'
'didmewithleg' anagrammed gives 'MIDDLEWEIGHT'.
(Other definitions for middleweight that I've seen before include "Boxer" , "Boxing category" .)