Set to refuse (7)
I believe the answer is:
decline
I believe this is a double definition.
'set' is the first definition.
(thesaurus)
'refuse' is the second definition.
('decline' can be a synonym of 'refuse')
'to' acts as a link.
(Other definitions for decline that I've seen before include "The classics student must often" , "Downturn - turn down" , "Dwindle" , "Fade" , "Refuse - to go down" .)