seer vs prognosticator

seer and prognosticator both are nouns.

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

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

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

Other hyponyms of seer include anticipant, anticipator, diviner, fantast, futurist, forecaster, predictor, soothsayer.

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