apocalypse vs calamity

apocalypse and calamity both are nouns.

Word	Noun	Adjective	Verb	Adverb
apocalypse	Yes	No	No	No
calamity	Yes	No	No	No

As nouns, calamity is a hypernym of apocalypse; that is, calamity is a word with a broader meaning than apocalypse:

apocalypse: a cosmic cataclysm in which God destroys the ruling powers of evil
calamity: an event resulting in great loss and misfortune

Other hypernyms of apocalypse include cataclysm, catastrophe, disaster, tragedy.

apocalypse (noun)	calamity (noun)
a cosmic cataclysm in which God destroys the ruling powers of evil	an event resulting in great loss and misfortune