Blood feud (8)
I believe the answer is:
vendetta
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">blood feud</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that blood feud can be written as vendetta)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for vendetta that I've seen before include "intense feud" , "Violent feud" , "Long-running quarrel" , "ongoing row" , "A prolonged feud, associated with Sicily" .)