change-up vs off-speed pitch

change-up and off-speed pitch both are nouns.

Word	Noun	Adjective	Verb	Adverb
change-up	Yes	No	No	No
off-speed pitch	Yes	No	No	No

As nouns, change-up and off-speed pitch are synonyms defined as:

change-up and off-speed pitch: a baseball thrown with little velocity when the batter is expecting a fastball

Other synonyms of change-up include change-of-pace, change-of-pace ball.

change-up (noun)	off-speed pitch (noun)
a baseball thrown with little velocity when the batter is expecting a fastball	a baseball thrown with little velocity when the batter is expecting a fastball