Very dry, as wine (4)
I believe the answer is:
brut
'very dry as wine' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for brut that I've seen before include "Dry (of champagne)" , "Unsweetened; very dry" , "one type of champagne" , "(Of sparkling wine) extremely dry" , "Of champagne, not sweet" .)