line up vs lineup

line up is not a noun while lineup is a noun.

Word	Noun	Adjective	Verb	Adverb
line up	No	No	Yes	No
lineup	Yes	No	No	No

line up (noun)	lineup (noun)
	(baseball) a list of batters in the order in which they will bat
	the schedule of programs for a particular period
	a line of persons arranged by police for inspection or identification

line up (verb)	lineup (verb)
place in a line or arrange so as to be parallel or straight
take one's position before a kick-off
arrange in ranks
form a queue, form a line, stand in line
get something or somebody for a specific purpose
form a line