Small dagger (4)
I believe the answer is:
dirk
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small dagger</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for dirk that I've seen before include "Scots dagger" , "Piercing instrument" , "which might get one stuck in Highlands" , "Duncan's killer?" , "Dagger with a long straight blade" .)