Yob partial to a fight (3)
I believe the answer is:
oaf
'yob' is the definition.
(both can mean a violent person)
'partial to a fight' is the wordplay.
'partial' indicates a hidden word.
'OAF' is hidden within 'to a fight'.
(Other definitions for oaf that I've seen before include "Yahoo" , "Oik" , "A clumsy boor" , "one of thick character" , "Lout, lummox" .)