Rumour I ignored — it’s not sweet (4)
I believe the answer is:
brut
'not sweet' is the definition.
(I've seen this in other clues)
'rumour i ignored' is the wordplay.
'rumour' becomes 'bruit' (synonyms).
'ignored' suggests deleting specific letters.
'bruit' with 'i' removed is 'BRUT'.
'it's' is the link.
(Other definitions for brut that I've seen before include "Dry (of champagne)" , "one type of champagne" , "Of champagne, not sweet" , "Unsweetened; very dry" , "(Of sparkling wine) extremely dry" .)