Conquest (6)
I believe the answer is:
defeat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">conquest</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for defeat that I've seen before include "best or worst" , "Beat (an opponent)" , "Conquest" , "Overthrow" , "Gain victory over" .)