prognostication vs portent

prognostication and portent both are nouns.

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

As nouns, prognostication and portent are synonyms defined as:

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

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