Wine bottle word (3)
(Other definitions for brut that I've seen before include "Of champagne, not sweet" , "(Of sparkling wines) very dry" , "(Of sparkling wine) extremely dry" , "Unsweetened; very dry" , "Dry (of champagne)" .)
'wine bottle word' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sec that I've seen before include "21 down, as wine" , "sort of function" , "period not lasting long" , "Mo or min?" , "sparkling?" .)