Vanquisher (9)
I believe the answer is:
conqueror
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vanquisher</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for conqueror that I've seen before include "William of Normandy" , "William's title after 1066 battle" , "Victor, winner" , "Military victor" , "For one, William" .)