run-up vs runup

run-up and runup both are nouns.

Word	Noun	Adjective	Verb	Adverb
run-up	Yes	No	No	No
runup	Yes	No	No	No

As nouns, run-up and runup are synonyms defined as:

run-up and runup: a substantial increase over a relatively short period of time

run-up (noun)	runup (noun)
the approach run during which an athlete gathers speed	a substantial increase over a relatively short period of time
a substantial increase over a relatively short period of time