Bar fight (4)
I believe the answer is:
spar
I believe this clue is a double definition.
'bar' is the first definition.
(I've seen this before)
'fight' is the second definition.
(sparring is a kind of fighting)
(Other definitions for spar that I've seen before include "Yard" , "Stout pole, nautically" , "Go a few rounds with the ship's pole" , "Box - girder" , "Train at boxing; mineral" .)