fold up vs crease

fold up is not a noun while crease is a noun.

Word	Noun	Adjective	Verb	Adverb
fold up	No	No	Yes	No
crease	Yes	No	Yes	No

As verbs, crease is a hyponym of fold up; that is, crease is a word with a more specific, narrower meaning than fold up:

Other hyponyms of fold up include crinkle, crumple, rumple, wrinkle.

As verbs, crease is a hyponym of fold up; that is, crease is a word with a more specific, narrower meaning than fold up:

fold up (noun)	crease (noun)
	a Malayan dagger with a wavy blade
	a slight depression or fold in the smoothness of a surface
	an angular or rounded shape made by folding

fold up (verb)	crease (verb)
become folded or folded up	become wrinkled or crumpled or creased
bend or lay so that one part covers the other	make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in; `crisp' is archaic
	make wrinkled or creased
	scrape gently