swim vs diving

swim and diving both are nouns.

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

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

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

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

swim (verb)	diving (verb)
travel through water
be afloat either on or below a liquid surface and not sink to the bottom
move as if gliding through water
be covered with or submerged in a liquid
be dizzy or giddy