slugger vs baseball player

slugger and baseball player both are nouns.

Word	Noun	Adjective	Verb	Adverb
slugger	Yes	No	No	No
baseball player	Yes	No	No	No

As nouns, baseball player is a hypernym of slugger; that is, baseball player is a word with a broader meaning than slugger:

Other hypernyms of slugger include ballplayer.

slugger (noun)	baseball player (noun)
(baseball) a ballplayer who is batting	an athlete who plays baseball
a boxer noted for an ability to deliver hard punches