Drink greedily (5)
(Other definitions for slurp that I've seen before include "Drink noisily" , "Consume (liquid) noisily" .)
'drink greedily' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gulp that I've seen before include "Noise made when swallowing too quickly" , "Swallow hurriedly" , "Swallow in large mouthfuls" , "Swallow audibly" , "Audible swallow" .)