furbish up vs improve

furbish up and improve both are verbs.

Word	Noun	Adjective	Verb	Adverb
furbish up	No	No	Yes	No
improve	No	No	Yes	No

As verbs, improve is a hypernym of furbish up; that is, improve is a word with a broader meaning than furbish up:

furbish up: restore by replacing a part or putting together what is torn or broken
improve: to make better

Other hypernyms of furbish up include ameliorate, amend, better, meliorate.

furbish up (verb)	improve (verb)
restore by replacing a part or putting together what is torn or broken	get better
	to make better