fortuneteller vs forecaster

fortuneteller and forecaster both are nouns.

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

As nouns, forecaster is a hypernym of fortuneteller; that is, forecaster is a word with a broader meaning than fortuneteller:

fortuneteller: a person who foretells your personal future
forecaster: someone who makes predictions of the future (usually on the basis of special knowledge)

Other hypernyms of fortuneteller include predictor, prognosticator, soothsayer.

fortuneteller (noun)	forecaster (noun)
a person who foretells your personal future	someone who makes predictions of the future (usually on the basis of special knowledge)