Cain's brother (4)
I believe the answer is:
abel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cain's brother</span>' is the definition.<br/ ><span class="explanation-format__explanation">(biblical figure)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for abel that I've seen before include "Brother killed by Cain" , "character in the Bible" , "First person killed" , "one killed early" , "Victim of 11" .)