athletics vs gymnastics

athletics and gymnastics both are nouns.

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

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

athletics: an active diversion requiring physical exertion and competition
gymnastics: a sport that involves exercises intended to display strength and balance and agility

athletics (noun)	gymnastics (noun)
an active diversion requiring physical exertion and competition	a sport that involves exercises intended to display strength and balance and agility
participation in sports events as an extracurricular activity
a contest between athletes