Not accept rubbish (6)
I believe the answer is:
refuse
This clue is a double definition.
'not accept' is the first definition.
('refuse' is the opposite to 'accept')
'rubbish' is the second definition.
(thesaurus)
(Other definitions for refuse that I've seen before include "Say no to - rubbish" , "Don't take the rubbish" , "Say no to - waste" , "Decline to jump; rubbish" , "Say no to garbage" .)