Thresh (5)
I believe the answer is:
flail
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thresh</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for flail that I've seen before include "Threshing device" , "Threshing implement" , "Weapon; swing wildly" , "Wave about wildly" , "thrash around" .)