dummy up vs dummy

dummy up is not a noun while dummy is a noun.

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

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

dummy up (noun)	dummy (noun)
	a figure representing the human form
	a cartridge containing an explosive charge but no bullet
	an ignorant or foolish person
	a person who does not talk

dummy up (adjective)	dummy (adjective)
	having the appearance of being real but lacking capacity to function

dummy up (verb)	dummy (verb)
refuse to talk or stop talking; fall silent	make a dummy of
make a dummy of