lookout vs look out

lookout is a noun but look out is not a noun.

Word	Noun	Adjective	Verb	Adverb
lookout	Yes	No	No	No
look out	No	No	Yes	No

lookout (noun)	look out (noun)
the act of looking out
a structure commanding a wide view of its surroundings
an elevated post affording a wide view
a person employed to keep watch for some anticipated event

lookout (verb)	look out (verb)
	to protect someone's interests
	be vigilant, be on the lookout or be careful