Auctioneer's mallet (5)
I believe the answer is:
gavel
'auctioneer's mallet' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gavel that I've seen before include "An auctioneer's wooden hammer" , "Judicial hammer" , "Small mallet" , "Judge's hammer" , "Ceremonial mallet" .)