water sport vs athletics

water sport and athletics both are nouns.

Word	Noun	Adjective	Verb	Adverb
water sport	Yes	No	No	No
athletics	Yes	No	No	No

As nouns, athletics is a hypernym of water sport; that is, athletics is a word with a broader meaning than water sport:

Other hypernyms of water sport include sport.

water sport (noun)	athletics (noun)
sports that involve bodies of water	an active diversion requiring physical exertion and competition
	participation in sports events as an extracurricular activity
	a contest between athletes