bone up vs bone

bone up is not a noun while bone is a noun.

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

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

Other synonyms of bone up include cram, drum, get up, grind away, mug up, swot, swot up.

bone up (noun)	bone (noun)
	a shade of white the color of bleached bones
	rigid connective tissue that makes up the skeleton of vertebrates
	the porous calcified substance from which bones are made

bone up (adjective)	bone (adjective)
	consisting of or made up of bone

bone up (verb)	bone (verb)
study intensively, as before an exam	remove the bones from
	study intensively, as before an exam