stay up vs keep up

stay up and keep up both are verbs.

Word	Noun	Adjective	Verb	Adverb
stay up	No	No	Yes	No
keep up	No	No	Yes	No

stay up (verb)	keep up (verb)
not go to bed	prevent from going to bed at night
	keep informed
	maintain a required pace or level
	keep in safety and protect from harm, decay, loss, or destruction
	lengthen or extend in duration or space