prognostic vs prognosticative

prognostic is a noun but prognosticative is not a noun.

Word	Noun	Adjective	Verb	Adverb
prognostic	Yes	Yes	No	No
prognosticative	No	Yes	No	No

As adjectives, prognostic and prognosticative are synonyms defined as:

prognostic and prognosticative: of or relating to prediction; having value for making predictions

Other synonyms of prognostic include predictive.

prognostic (noun)	prognosticative (noun)
a sign of something about to happen

prognostic (adjective)	prognosticative (adjective)
of or relating to prediction; having value for making predictions	of or relating to prediction; having value for making predictions