Auctioneer's hammer (5)
I believe the answer is:
gavel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">auctioneer's hammer</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 gavel that I've seen before include "Ceremonial mallet" , "Mason's hammer" , "Chairman's hammer" , "equipment for auctioneer" , "Small hammer" .)