One confining another (6)
I believe the answer is:
captor
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one confining another</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 captor that I've seen before include "One who takes a prisoner" , "Guard" , "He catches someone" , "One taking a prisoner" , "One confining another" .)