bathroom vs closet

bathroom and closet both are nouns.

Word	Noun	Adjective	Verb	Adverb
bathroom	Yes	No	No	No
closet	Yes	No	Yes	No

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

bathroom (noun)	closet (noun)
a room (as in a residence) containing a bathtub or shower and usually a washbasin and toilet	a small private room for study or prayer
a room or building equipped with one or more toilets	a toilet in Britain
	a tall piece of furniture that provides storage space for clothes; has a door and rails or hooks for hanging clothes
	a small room (or recess) or cabinet used for storage space

bathroom (verb)	closet (verb)
	confine to a small space, as for intensive work