cataract vs waterfall

cataract and waterfall both are nouns.

Word	Noun	Adjective	Verb	Adverb
cataract	Yes	No	No	No
waterfall	Yes	No	No	No

As nouns, waterfall is a hypernym of cataract; that is, waterfall is a word with a broader meaning than cataract:

Other hypernyms of cataract include falls.

cataract (noun)	waterfall (noun)
a large waterfall; violent rush of water over a precipice	a steep descent of the water of a river
an eye disease that involves the clouding or opacification of the natural lens of the eye