Repair broken fencing tool (6)
I believe the answer is:
rapier
'fencing tool' is the definition.
(I've seen this in another clue)
'repair broken' is the wordplay.
'broken' indicates anagramming the letters.
'repair' with letters rearranged gives 'RAPIER'.
(Other definitions for rapier that I've seen before include "Long slender sword" , "Straight sword with narrow blade" , "A fencing sword for repair" , "Straight narrow sword with two edges" , "Narrow sword with two-edged blade" .)