All-out brawl (5)
I believe the answer is:
melee
'all-out brawl' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for melee that I've seen before include "Fracas" , "Rumpus" , "confused group" , "A confused free-for-all" , "Affray; muddled group" .)