Ruler with absolute power (8)
I believe the answer is:
autocrat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ruler with absolute 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 autocrat that I've seen before include "who's in charge? Absolutely!" , "Person with unlimited power, kind of dictator" , "All-powerful ruler" , "Despot, tyrant" , "Dictatorial person" .)