eternity vs being

eternity and being both are nouns.

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

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

eternity: a state of eternal existence believed in some religions to characterize the afterlife
being: the state or fact of existing

Other hypernyms of eternity include beingness, existence, face of the earth.

eternity (noun)	being (noun)
a state of eternal existence believed in some religions to characterize the afterlife	a living thing that has (or can develop) the ability to act or function independently
time without end	the state or fact of existing
a seemingly endless time interval (waiting)