pop up vs crop up

pop up and crop up both are verbs.

Word	Noun	Adjective	Verb	Adverb
pop up	No	No	Yes	No
crop up	No	No	Yes	No

As verbs, pop up and crop up are synonyms defined as:

pop up and crop up: appear suddenly or unexpectedly; happen unexpectedly

Other synonyms of pop up include burst out, pop, pop out.

pop up (verb)	crop up (verb)
appear suddenly or unexpectedly; happen unexpectedly	appear suddenly or unexpectedly; happen unexpectedly