Swordsman (6)
I believe the answer is:
fencer
'swordsman' is the definition.
(fencers use swords)
This is the entire clue.
(Other definitions for fencer that I've seen before include "He sports with swords" , "One with flashing blade" , "A sportsman with swords" , "His sport is swordplay" , "secures a boundary" .)