Repair damaged sword (6)
I believe the answer is:
rapier
'sword' is the definition.
(sword used in fencing)
'repair damaged' is the wordplay.
'damaged' indicates an anagram.
'repair' with letters rearranged gives 'RAPIER'.
(Other definitions for rapier that I've seen before include "A small spring flower" , "Light sword" , "Fine-bladed sword" , "Sword for thrusting" , "Straight narrow sword with two edges" .)