fort up vs fort

fort up is not a noun while fort is a noun.

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

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

fort up and fort: gather in, or as if in, a fort, as for protection or defense

fort up (noun)	fort (noun)
	a fortified defensive structure
	a fortified military post where troops are stationed

fort up (verb)	fort (verb)
gather in, or as if in, a fort, as for protection or defense	station (troops) in a fort
	enclose by or as if by a fortification
	gather in, or as if in, a fort, as for protection or defense