black eye vs natural event

black eye and natural event both are nouns.

Word	Noun	Adjective	Verb	Adverb
black eye	Yes	No	No	No
natural event	Yes	No	No	No

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

black eye: an unfortunate happening that hinders or impedes; something that is thwarting or frustrating
natural event: an event that happens

Other hypernyms of black eye include happening, occurrence, occurrent.

black eye (noun)	natural event (noun)
an unfortunate happening that hinders or impedes; something that is thwarting or frustrating	an event that happens
a swollen bruise caused by a blow to the eye
a bad reputation