Large order for drink (5)
I believe the answer is:
lager
'drink' is the definition.
(lager is a kind of drink)
'large order' is the wordplay.
'order' indicates an anagram.
'large' is an anagram of 'LAGER'.
'for' is the link.
(Other definitions for lager that I've seen before include "Drink - 5 down (anag)" , "Pilsner, for example" , "The drink could be regal" , "Local offering" , "light ale" .)