Act of shutting (7)
I believe the answer is:
closure
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">act of shutting</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 closure that I've seen before include "Settlement giving psychological satisfaction" , "Final shutdown" , "Ending" , "Stoppage" , "Co-rules (anag.)" .)