pipe up vs pipe

pipe up is not a noun while pipe is a noun.

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

As verbs, pipe up and pipe are synonyms defined as:

Other synonyms of pipe up include shriek, shrill.

pipe up (noun)	pipe (noun)
	a long tube made of metal or plastic that is used to carry water or oil or gas etc.
	a tube with a small bowl at one end; used for smoking tobacco
	the flues and stops on a pipe organ
	a tubular wind instrument
	a hollow cylindrical shape