Seizure of power (4)
I believe the answer is:
coup
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">seizure of power</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 coup that I've seen before include "Violent seizure of power" , "Brilliant and notable success" , "Brilliant stroke" , "Accomplishment, exploit" , "Hostile takeover" .)