athletics vs judo

athletics and judo both are nouns.

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

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

athletics: an active diversion requiring physical exertion and competition
judo: a sport adapted from jujitsu (using principles of not resisting) and similar to wrestling; developed in Japan

athletics (noun)	judo (noun)
an active diversion requiring physical exertion and competition	a sport adapted from jujitsu (using principles of not resisting) and similar to wrestling; developed in Japan
participation in sports events as an extracurricular activity
a contest between athletes