lifter vs jock

lifter and jock both are nouns.

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

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

Other hypernyms of lifter include athlete.

lifter (noun)	jock (noun)
an athlete who lifts barbells	a support for the genitals worn by men engaging in strenuous exercise
a thief who steals goods that are in a store	a person trained to compete in sports