Hearty gulp (4)
I believe the answer is:
swig
'hearty gulp' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for swig that I've seen before include "Swallow (drink) greedily" , "Gulp of drink" , "Slug" , "(Take) quick drink from bottle" , "Drink quickly from bottle" .)