fortuneteller vs sibyl

fortuneteller and sibyl both are nouns.

Word	Noun	Adjective	Verb	Adverb
fortuneteller	Yes	No	No	No
sibyl	Yes	No	No	No

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

Other hyponyms of fortuneteller include chiromancer, palmist, palmister.

fortuneteller (noun)	sibyl (noun)
a person who foretells your personal future	(ancient Rome) a woman who was regarded as an oracle or prophet
	a woman who tells fortunes