southpaw vs pitcher

southpaw and pitcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
southpaw	Yes	No	No	No
pitcher	Yes	No	No	No

As nouns, pitcher is a hypernym of southpaw; that is, pitcher is a word with a broader meaning than southpaw:

Other hypernyms of southpaw include hurler, twirler.

southpaw (noun)	pitcher (noun)
a person who uses the left hand with greater skill than the right	the position on a baseball team of the player who throws the ball for a batter to try to hit
a baseball pitcher who throws the ball with the left hand	an open vessel with a handle and a spout for pouring
	(baseball) the person who does the pitching
	(botany) a leaf that is modified in such a way as to resemble a pitcher or ewer
	the quantity contained in a pitcher