Fist fight (5-2)
I believe the answer is:
punch-up
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fist fight</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for punch-up that I've seen before include "Brawl (colloq.)" , "Fisticuffs incident" , "An informal brawl, a fight with fists" , "An informal fist-fight or brawl - strike vertically?" , "Street brawl" .)