nightcap vs drink

nightcap and drink both are nouns.

Word	Noun	Adjective	Verb	Adverb
nightcap	Yes	No	No	No
drink	Yes	No	Yes	No

As nouns, drink is a hypernym of nightcap; that is, drink is a word with a broader meaning than nightcap:

nightcap (noun)	drink (noun)
the final game of a double header	the act of drinking alcoholic beverages to excess
a cloth cap worn in bed	the act of swallowing
an alcoholic drink taken at bedtime; often alcoholic	any liquid suitable for drinking
	a single serving of a beverage
	any large deep body of water

nightcap (verb)	drink (verb)
	be fascinated or spell-bound by; pay close attention to
	take in liquids
	consume alcohol
	drink excessive amounts of alcohol; be an alcoholic
	propose a toast to