perk up vs perk

perk up is not a noun while perk is a noun.

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

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

Other synonyms of perk up include gain vigor, percolate, pick up.

perk up (noun)	perk (noun)
	an incidental benefit awarded for certain types of employment (especially if it is regarded as a right)

perk up (verb)	perk (verb)
gain or regain energy	gain or regain energy
cause to be alert and energetic