Drink like a fish (4)
I believe the answer is:
tope
I believe this is a double definition.
'drink' is the first definition.
('tope' can be a synonym of 'drink')
'a fish' is the second definition.
(thesaurus)
'like' is the link.
(Other definitions for tope that I've seen before include "Drink heavily" , "Drink hard regularly" , "Small grey requiem shark" , "Drink excessively like poet" , "Drink a lot like poet" .)