fortune teller vs forecaster

fortune teller and forecaster both are nouns.

Word	Noun	Adjective	Verb	Adverb
fortune teller	Yes	No	No	No
forecaster	Yes	No	No	No

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

fortune teller: 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 fortune teller include predictor, prognosticator, soothsayer.

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