death knell vs prognostic

death knell and prognostic both are nouns.

Word	Noun	Adjective	Verb	Adverb
death knell	Yes	No	No	No
prognostic	Yes	Yes	No	No

As nouns, prognostic is a hypernym of death knell; that is, prognostic is a word with a broader meaning than death knell:

Other hypernyms of death knell include omen, portent, presage, prodigy, prognostication.

death knell (noun)	prognostic (noun)
a bell rung to announce a death	a sign of something about to happen
an omen of death or destruction

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