swimming vs diving

swimming and diving both are nouns.

Word	Noun	Adjective	Verb	Adverb
swimming	Yes	Yes	No	No
diving	Yes	No	No	No

As nouns, diving is a hyponym of swimming; that is, diving is a word with a more specific, narrower meaning than swimming:

Other hyponyms of swimming include bathe, skinny-dip, dip, plunge, dive, floating, natation, skin-dive, skin diving.

swimming (noun)	diving (noun)
the act of swimming	a headlong plunge into water
	an athletic competition that involves diving into water

swimming (adjective)	diving (adjective)
applied to a fish depicted horizontally
filled or brimming with tears