Oblige (6)
I believe the answer is:
compel
'oblige' is the definition.
(I know that oblige can be written as compel)
This is the entire clue.
(Other definitions for compel that I've seen before include "Bring about by force" , "Coerce, force to obey" , "Use force or influence to make something happen" , "Force, oblige to do something" , "'Force, oblige (6)'" .)