Supporter of monarchy (8)
I believe the answer is:
royalist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">supporter of monarchy</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 royalist that I've seen before include "Monarch's supporter" , "Civil War participant" , "Monarchist" , "one in civil war" , "rightwinger?" .)