Refuse, in a terrible rage, to accept the case (7)
I believe the answer is:
garbage
'refuse' is the definition.
(synonyms)
'a terrible rage to accept the case' is the wordplay.
'a terrible' is an anagram indicator.
'to accept' indicates putting letters inside.
'the case' becomes 'bag' (bag is a kind of case).
'rage' with letters rearranged gives 'gare'.
'gare' placed around 'bag' is 'GARBAGE'.
'in' acts as a link.
(Other definitions for garbage that I've seen before include "US rubbish" , "'Refuse, rubbish (7)'" , "Nonsense!" , "Refuse - worthless talk" , "Refuse - a beggar (anag)" .)