hitter vs whiffer

hitter and whiffer both are nouns.

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

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

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

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

hitter (noun)	whiffer (noun)
(baseball) a ballplayer who is batting	a batter who strikes out by swinging at and missing the third strike
someone who hits