For which happily quit ale? (7)
I believe the answer is:
tequila
'for' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I can't see?
'happily quit ale?' is the wordplay.
'quit ale' anagrams to 'TEQUILA'.
Though, I am not sure how this is indicated.
'which' is the link.
Can you help me to learn more?
(Other definitions for tequila that I've seen before include "Mexican liquor made from agave" , "Distilled agave drink" , "Cocktail -- 1988 American crime film -- equaliser units (anag)" , "Equal it! (anag)" , "Mexican tipple" .)