Double-edged sword (6)
I believe the answer is:
rapier
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">double-edged sword</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rapier that I've seen before include "Thrusting weapon" , "Narrow sword with two-edged blade" , "Straight narrow sword with two edges" , "Light sword" , "A thin double-edged sword" .)