bad luck vs cataclysm

bad luck and cataclysm both are nouns.

Word	Noun	Adjective	Verb	Adverb
bad luck	Yes	No	No	No
cataclysm	Yes	No	No	No

As nouns, cataclysm is a hyponym of bad luck; that is, cataclysm is a word with a more specific, narrower meaning than bad luck:

bad luck: unnecessary and unforeseen trouble resulting from an unfortunate event
cataclysm: an event resulting in great loss and misfortune

bad luck (noun)	cataclysm (noun)
unnecessary and unforeseen trouble resulting from an unfortunate event	an event resulting in great loss and misfortune
an unpredictable outcome that is unfortunate	a sudden violent change in the earth's surface
an unfortunate state resulting from unfavorable outcomes