Compel; violence (5)
I believe the answer is:
force
I believe this clue is a double definition.
'compel' is the first definition.
(I know that force is a type of compel)
'violence' is the second definition.
(I know that violence can be written as force)
(Other definitions for force that I've seen before include "Strength, power" , "Physical strength" , "Royal Air - -" , "Impel, coerce" , "Power; army" .)