drinker vs gulper

drinker and gulper both are nouns.

Word	Noun	Adjective	Verb	Adverb
drinker	Yes	No	No	No
gulper	Yes	No	No	No

As nouns, gulper is a hyponym of drinker; that is, gulper is a word with a more specific, narrower meaning than drinker:

Other hyponyms of drinker include guzzler, quaffer, sipper, sucker.

drinker (noun)	gulper (noun)
a person who drinks alcoholic beverages (especially to excess)	a drinker who swallows large amounts greedily
a person who drinks liquids