Tough husband wearing drag (4)
I believe the answer is:
thug
'tough' is the definition.
(both can mean a violent person)
'husband wearing drag' is the wordplay.
'husband' becomes 'h'.
'wearing' indicates putting letters inside.
'drag' becomes 'tug' (tug can mean to drag or pull).
'h' inserted within 'tug' is 'THUG'.
(Other definitions for thug that I've seen before include "A vicious or brutal ruffian" , "violent gang member" , "Violent criminal" , "violent man" , "Indian strangler - criminal" .)