Complain audibly at beverage (4)
I believe the answer is:
wine
'beverage' is the definition.
(wine is a kind of beverage)
'complain audibly' is the wordplay.
'complain' becomes 'whine' (whining is a kind of complaining).
'audibly' shows a homophone (sound like).
'whine' is a homophone of 'WINE'.
'at' acts as a link.
(Other definitions for wine that I've seen before include "Something made with 16?" , "Fermented grape juice" , "Drink made from grapes" , "A sweet white cargo of Masefield's" , "champagne, perhaps" .)