gymnast vs jock

gymnast and jock both are nouns.

Word	Noun	Adjective	Verb	Adverb
gymnast	Yes	No	No	No
jock	Yes	No	No	No

As nouns, jock is a hypernym of gymnast; that is, jock is a word with a broader meaning than gymnast:

Other hypernyms of gymnast include athlete.

gymnast (noun)	jock (noun)
an athlete who is skilled in gymnastics	a support for the genitals worn by men engaging in strenuous exercise
	a person trained to compete in sports