accident vs natural event

accident and natural event both are nouns.

Word	Noun	Adjective	Verb	Adverb
accident	Yes	No	No	No
natural event	Yes	No	No	No

As nouns, natural event is a hypernym of accident; that is, natural event is a word with a broader meaning than accident:

accident: anything that happens suddenly or by chance without an apparent cause
natural event: an event that happens

Other hypernyms of accident include happening, occurrence, occurrent.

accident (noun)	natural event (noun)
anything that happens suddenly or by chance without an apparent cause	an event that happens
an unfortunate mishap; especially one causing damage or injury