Ridiculously large drink (5)
I believe the answer is:
lager
'drink' is the definition.
(lager is a kind of drink)
'ridiculously large' is the wordplay.
'ridiculously' is an anagram indicator (I've seen this in other clues).
'large' anagrammed gives 'LAGER'.
(Other definitions for lager that I've seen before include "Light beer; sounds like camp" , "A brew" , "African camp" , "Drink - 5 down (anag)" , "Local offering" .)