skiing vs athletics

skiing and athletics both are nouns.

Word	Noun	Adjective	Verb	Adverb
skiing	Yes	No	No	No
athletics	Yes	No	No	No

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

Other hypernyms of skiing include sport.

skiing (noun)	athletics (noun)
a sport in which participants must travel on skis	an active diversion requiring physical exertion and competition
	participation in sports events as an extracurricular activity
	a contest between athletes