postdiluvian vs being

postdiluvian and being both are nouns.

Word	Noun	Adjective	Verb	Adverb
postdiluvian	Yes	Yes	No	No
being	Yes	No	No	No

As nouns, being is a hypernym of postdiluvian; that is, being is a word with a broader meaning than postdiluvian:

postdiluvian: anything living after Noah's flood
being: a living thing that has (or can develop) the ability to act or function independently

Other hypernyms of postdiluvian include organism.

postdiluvian (noun)	being (noun)
anything living after Noah's flood	a living thing that has (or can develop) the ability to act or function independently
	the state or fact of existing

postdiluvian (adjective)	being (adjective)
existing or occurring after Noah's flood