prognosticator vs seer

prognosticator and seer both are nouns.

Word	Noun	Adjective	Verb	Adverb
prognosticator	Yes	No	No	No
seer	Yes	No	No	No

As nouns, seer is a hypernym of prognosticator; that is, seer is a word with a broader meaning than prognosticator:

prognosticator: someone who makes predictions of the future (usually on the basis of special knowledge)
seer: a person with unusual powers of foresight

Other hypernyms of prognosticator include illusionist, visionary.

prognosticator (noun)	seer (noun)
someone who makes predictions of the future (usually on the basis of special knowledge)	a person with unusual powers of foresight
	an authoritative person who divines the future
	an observer who perceives visually