Family feud (8)
I believe the answer is:
vendetta
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">family feud</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 vendetta that I've seen before include "Blood-feud between families" , "A prolonged feud, associated with Sicily" , "Sicilian blood feud" , "murderous campaign?" , "Unremitting battle" .)