Supreme commander (13)
I believe the answer is:
generalissimo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">supreme commander</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 generalissimo that I've seen before include "Political and military leader" , "Commander-in-chief" , "Supreme commander (It.), title used by Franco" , "Top commander" , "Supreme commander of combined military forces" .)