Force, oblige (6)
I believe the answer is:
compel
I believe this clue is a double definition.
'force' is the first definition.
(I know this)
'oblige' is the second definition.
(I know that oblige can be written as compel)
(Other definitions for compel that I've seen before include "Bring about by force" , "'Force, oblige (6)'" , "Urge on, force" , "Use force or influence to make something happen" , "Use force, oblige" .)