ballplayer vs athlete

ballplayer and athlete both are nouns.

Word	Noun	Adjective	Verb	Adverb
ballplayer	Yes	No	No	No
athlete	Yes	No	No	No

As nouns, athlete is a hypernym of ballplayer; that is, athlete is a word with a broader meaning than ballplayer:

Other hypernyms of ballplayer include jock, participant, player.

ballplayer (noun)	athlete (noun)
an athlete who plays baseball	a person trained to compete in sports