Compelled; strained (6)
I believe the answer is:
forced
I believe this clue is a double definition.
'compelled' is the first definition.
(forcing is a kind of compelling)
'strained' is the second definition.
(I know that strained can be written as forced)
(Other definitions for forced that I've seen before include "compulsory" , "Not natural" , "Like early rhubarb" , "Compelled, made to obey" , "Compelled or strained" .)