Cocktail, some briefly that awful chap guzzles (9)
I believe the answer is:
manhattan
'cocktail' is the definition.
(I know that Manhattan is a type of cocktail)
'some briefly that awful chap guzzles' is the wordplay.
I cannot really see how this works, but
'some' could be 'a' and 'a' is located in the answer.
an anagram of 'that' is 'hatt' which is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for manhattan that I've seen before include "Vermouth and whisky cocktail - New York borough" , "Vermouth and whiskey, with a dash of bitters" , "Cocktail of whiskey and sweet vermouth" , "Cocktail consisting of whisky, vermouth and bitters" , "Island of New York - cocktail" .)