half gainer vs diving

half gainer and diving both are nouns.

Word	Noun	Adjective	Verb	Adverb
half gainer	Yes	No	No	No
diving	Yes	No	No	No

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

half gainer: a dive in which the diver throws the feet forward and up to complete a half backward somersault and enters the water facing the diving board
diving: a headlong plunge into water

Other hypernyms of half gainer include dive.

half gainer (noun)	diving (noun)
a dive in which the diver throws the feet forward and up to complete a half backward somersault and enters the water facing the diving board	a headlong plunge into water
	an athletic competition that involves diving into water