Limbs used in battle (4)
I believe the answer is:
arms
'limbs' is the definition.
(I know this)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for arms that I've seen before include "International competition for weapons" , "Crest - guns" , "pacifists won't take up" , "Weapons, collectively" , "Supplies weapons" .)