Mexican drink (7)
I believe the answer is:
tequila
'mexican drink' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tequila that I've seen before include "Mexican agave spirit" , "Mexican liquor made from agave" , "Is there another drink to equal it?" , "Cocktail -- 1988 American crime film -- equaliser units (anag)" , "Equal it! (anag)" .)