slugger vs whiffer

slugger and whiffer both are nouns.

Word	Noun	Adjective	Verb	Adverb
slugger	Yes	No	No	No
whiffer	Yes	No	No	No

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

slugger: (baseball) a ballplayer who is batting
whiffer: a batter who strikes out by swinging at and missing the third strike

Other hyponyms of slugger include bunter, designated hitter, pinch hitter, switch-hitter.

slugger (noun)	whiffer (noun)
(baseball) a ballplayer who is batting	a batter who strikes out by swinging at and missing the third strike
a boxer noted for an ability to deliver hard punches