Foamy brew (4)
I believe the answer is:
beer
'foamy brew' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for beer that I've seen before include "pint" , "Hopped drink" , "Brewery product" , ""Give me a woman who loves __ and I will conquer the world" (Kaiser Wilhelm)" , "... this at pub?" .)