fold up vs furrow

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

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

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

fold up (noun)	furrow (noun)
	a long shallow trench in the ground (especially one made by a plow)
	a slight depression or fold in the smoothness of a surface

fold up (verb)	furrow (verb)
become folded or folded up	hollow out in the form of a furrow or groove
bend or lay so that one part covers the other	make wrinkled or creased
	cut a furrow into a columns