High-quality brandy (6)
I believe the answer is:
cognac
'high-quality brandy' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cognac that I've seen before include "Type of brandy" , "French brandy region" , "Brandy of the French Charente" , "High quality brandy" , "High-quality brandy" .)