playing vs pitching

playing and pitching both are nouns.

Word	Noun	Adjective	Verb	Adverb
playing	Yes	No	No	No
pitching	Yes	No	No	No

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

Other hyponyms of playing include bowling, catching, golfing, cheesing.

playing (noun)	pitching (noun)
the action of taking part in a game or sport or other recreation	(baseball) playing the position of pitcher on a baseball team
the act of playing a musical instrument	abrupt up-and-down motion (as caused by a ship or other conveyance)
the performance of a part or role in a drama