ruck up vs ruck

ruck up is not a noun while ruck is a noun.

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

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

Other synonyms of ruck up include pucker.

ruck up (noun)	ruck (noun)
	a crowd especially of ordinary or undistinguished persons or things
	an irregular fold in an otherwise even surface (as in cloth)

ruck up (verb)	ruck (verb)
become wrinkled or drawn together	become wrinkled or drawn together