Ruffian, lout (4)
I believe the answer is:
thug
I believe this is a double definition.
'ruffian' is the first definition.
(both can mean a violent person)
'lout' is the second definition.
(I have seen 'Violent lout ' mean 'thug' so perhaps 'lout' could also mean 'thug')
(Other definitions for thug that I've seen before include "Hood" , "Gorilla" , "A vicious or brutal ruffian" , "undesirable character" , "Burrowing crustacean" .)