One who dies for a cause (6)
I believe the answer is:
martyr
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one who dies for a cause</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 martyr that I've seen before include "Sufferer for faith" , "Victim of suffering" , "put at stake?" , "One who dies for a cause" , "One who gives his life for a cause" .)