Knock-down-drag-out (5)
I believe the answer is:
melee
'knock-down-drag-out' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for melee that I've seen before include "A confused fight or muddle" , "Skirmish" , "Confused fight or scuffle" , "Scrimmage" , "Fracas" .)