look up vs look

look up is not a noun while look is a noun.

Word	Noun	Adjective	Verb	Adverb
look up	No	No	Yes	No
look	Yes	No	Yes	No

look up (noun)	look (noun)
	the act of directing the eyes toward something and perceiving it visually; look
	physical appearance
	the feelings expressed on a person's face
	the general atmosphere of a place or situation and the effect that it has on people

look up (verb)	look (verb)
seek information from	to physically appear a certain way to another individual or group
	look forward to the probable occurrence of
	have faith or confidence in
	convey by one's expression
	perceive with attention; direct one's gaze towards; look
	give a certain impression of being something or having a certain aspect
	search or seek
	take charge of or deal with
	be oriented in a certain direction, often with respect to another reference point; be opposite to
	accord in appearance with