pop-fly vs pop-up

pop-fly and pop-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
pop-fly	Yes	No	No	No
pop-up	Yes	No	No	No

As nouns, pop-fly and pop-up are synonyms defined as:

Other synonyms of pop-fly include pop fly.

pop-fly (noun)	pop-up (noun)
a short high fly ball	a short high fly ball
	a store that is open for a limited period of time on temporary premises
	a book (usually for children) that contains one or more pages such that a three-dimensional structure rises up when a page is opened