Pentathlon sword (4)
I believe the answer is:
epee
'pentathlon sword' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for epee that I've seen before include "Fencer's weapon" , "sharp-edged implement" , "piece of fencing" , "Fencer's sword" , "Fencing sword, heavier than a foil" .)