Affaire d'honneur (4)
I believe the answer is:
duel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">affaire d'honneur</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for duel that I've seen before include "Combat to settle a row" , "Single combat" , "Contest between two with deadly weapons" , "Prearranged fight with deadly weapons between two people" , "honourable affair" .)