restroom vs toilet

restroom and toilet both are nouns.

Word	Noun	Adjective	Verb	Adverb
restroom	Yes	No	No	No
toilet	Yes	No	No	No

As nouns, toilet is a hypernym of restroom; that is, toilet is a word with a broader meaning than restroom:

Other hypernyms of restroom include facility, bathroom, can, john, lav, lavatory, privy.

restroom (noun)	toilet (noun)
a toilet that is available to the public	the act of dressing and preparing yourself
	a room or building equipped with one or more toilets
	a plumbing fixture for defecation and urination
	misfortune resulting in lost effort or money