hurler vs thrower

hurler and thrower both are nouns.

Word	Noun	Adjective	Verb	Adverb
hurler	Yes	No	No	No
thrower	Yes	No	No	No

As nouns, thrower is a hypernym of hurler; that is, thrower is a word with a broader meaning than hurler:

hurler: (baseball) the person who does the pitching
thrower: someone who projects something (especially by a rapid motion of the arm)

Other hypernyms of hurler include ballplayer, baseball player.

hurler (noun)	thrower (noun)
(baseball) the person who does the pitching	someone who projects something (especially by a rapid motion of the arm)
	a craftsman who shapes pottery on a potter's wheel and bakes them in a kiln
	a person who twists silk or rayon filaments into a thread or yarn