lefthander vs lefty

lefthander and lefty both are nouns.

Word	Noun	Adjective	Verb	Adverb
lefthander	Yes	No	No	No
lefty	Yes	No	No	No

As nouns, lefthander and lefty are synonyms defined as:

lefthander and lefty: a baseball pitcher who throws the ball with the left hand

Other synonyms of lefthander include left-handed pitcher, left-hander, left hander, southpaw.

lefthander (noun)	lefty (noun)
a baseball pitcher who throws the ball with the left hand	a person who uses the left hand with greater skill than the right
	a baseball pitcher who throws the ball with the left hand