Twist fighting power (4)
I believe the answer is:
warp
'twist' is the definition.
(thesaurus)
'fighting power' is the wordplay.
'fighting' becomes 'war'.
'power' becomes 'p'.
'war'+'p'='WARP'
(Other definitions for warp that I've seen before include "Distort as wood may from heat" , "Misintepret" , "Twist out of shape" , "Crane fly larva" , "Abnormality in character" .)