belly flopper vs diving

belly flopper and diving both are nouns.

Word	Noun	Adjective	Verb	Adverb
belly flopper	Yes	No	No	No
diving	Yes	No	No	No

As nouns, diving is a hypernym of belly flopper; that is, diving is a word with a broader meaning than belly flopper:

belly flopper: a dive in which the abdomen bears the main force of impact with the water
diving: a headlong plunge into water

Other hypernyms of belly flopper include dive.

belly flopper (noun)	diving (noun)
a dive in which the abdomen bears the main force of impact with the water	a headlong plunge into water
	an athletic competition that involves diving into water