Clubs are able to sell back drink (6)
I believe the answer is:
cognac
'drink' is the definition.
(Cognac is an example)
'clubs are able to sell back' is the wordplay.
'clubs' becomes 'c' (abbreviation in card games).
'are able' becomes 'can'.
'to sell' becomes 'go' (I can't justify this - if you can you should give a lot more credence to this answer).
'back' says the letters should be written in reverse.
'can'+'go'='cango'
'cango' reversed gives 'ognac'.
'c'+'ognac'='COGNAC'
Can you help me to learn more?
(Other definitions for cognac that I've seen before include "High-quality brandy" , "Brandy of the French Charente" , "Liquor" , "Brandy as for Napoleon (6)." , "warmer" .)