Sword held by some peers (4)
I believe the answer is:
epee
'sword' is the definition.
(sword used in fencing)
'held by some peers' is the wordplay.
'held by' indicates the answer is hidden within the clue.
'EPEE' is hidden in the letters of 'some peers'.
(Other definitions for epee that I've seen before include "Fighting blade" , "Olympic event" , "Narrow fencing sword" , "Duelling blade" , "piece of fencing" .)