Drink quite a large shot (7)
I believe the answer is:
tequila
'drink' is the definition.
(tequila is a kind of drink)
'quite a large shot' is the wordplay.
'large' becomes 'l'.
'shot' is an anagram indicator.
'quite'+'a'+'l'='quiteal'
'quiteal' anagrammed gives 'TEQUILA'.
(Other definitions for tequila that I've seen before include "Liquor made from the agave plant" , "Is there another drink to equal it?" , "Distilled agave drink" , "Mexican alcoholic drink" , "Quit ale for Mexican spirit" .)