portent vs prognostication

portent and prognostication both are nouns.

Word	Noun	Adjective	Verb	Adverb
portent	Yes	No	No	No
prognostication	Yes	No	No	No

As nouns, portent and prognostication are synonyms defined as:

Other synonyms of portent include omen, presage, prodigy, prognostic.

portent (noun)	prognostication (noun)
a sign of something about to happen	knowledge of the future (usually said to be obtained from a divine source)
	a statement made about the future
	a sign of something about to happen