Culbertson coup (4)
I believe the answer is:
slam
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">culbertson coup</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for slam that I've seen before include "major contract" , "Ambitious contract" , "Shut loudly and forcibly" , "Severely criticise; shut (a door) forcefully" , "Shut hard" .)