Sword combative peer holds (4)
I believe the answer is:
epee
'sword' is the definition.
(sword used in fencing)
'combative peer holds' is the wordplay.
'holds' says the answer is hidden in the clue.
'EPEE' is hidden within 'combative peer'.
(Other definitions for epee that I've seen before include "Olympic event" , "Rapier" , "Use it to fence" , "piece of fencing" , "sharp-edged implement" .)