Litigator (9)
I believe the answer is:
plaintiff
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">litigator</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that plaintiff is a type of litigator)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for plaintiff that I've seen before include "The one taking the court action" , "One bringing a lawsuit" , "one prompting action" , "Temporary disappearances of a heavenly body" , "one in suit" .)