Refuse to make a scathing comment (7)
I believe the answer is:
rubbish
This clue is a double definition.
'refuse' is the first definition.
(refuse can mean rubbish or waste)
'make a scathing comment' is the second definition.
(I've seen this before)
'to' is the link.
(Other definitions for rubbish that I've seen before include "Pan" , "Codswallop or trash" , "Awful" , "Nonsense or refuse" , "'Trash, tripe (7)'" .)