Shut hard (4)
I believe the answer is:
slam
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">shut hard</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 slam that I've seen before include "A grand one is 13 tricks" , "Shut hard" , "Shut (door) with force" , "Close noisily" , "big contract" .)