tsunami vs disaster

tsunami and disaster both are nouns.

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

As nouns, disaster is a hypernym of tsunami; that is, disaster 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
disaster: an event resulting in great loss and misfortune

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

tsunami (noun)	disaster (noun)
a cataclysm resulting from a destructive sea wave caused by an earthquake or volcanic eruption	an act that has disastrous consequences
	an event resulting in great loss and misfortune
	a state of extreme (usually irremediable) ruin and misfortune