Selectively slaughter (4)
I believe the answer is:
cull
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">selectively slaughter</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 cull that I've seen before include "Destroy selectively" , "Remove from herd" , "Choose the best from" , "Exercise to reduce numbers" , "Choose; thin out" .)