tsunami vs cataclysm

tsunami and cataclysm both are nouns.

Word	Noun	Adjective	Verb	Adverb
tsunami	Yes	No	No	No
cataclysm	Yes	No	No	No

As nouns, cataclysm is a hypernym of tsunami; that is, cataclysm is a word with a broader meaning than tsunami:

tsunami: a cataclysm resulting from a destructive sea wave caused by an earthquake or volcanic eruption
cataclysm: an event resulting in great loss and misfortune

Other hypernyms of tsunami include calamity, catastrophe, disaster, tragedy, moving ridge, wave.

tsunami (noun)	cataclysm (noun)
a cataclysm resulting from a destructive sea wave caused by an earthquake or volcanic eruption	an event resulting in great loss and misfortune
	a sudden violent change in the earth's surface