unfasten vs open up

unfasten and open up both are verbs.

Word	Noun	Adjective	Verb	Adverb
unfasten	No	No	Yes	No
open up	No	No	Yes	No

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

Other hypernyms of unfasten include open.

unfasten (verb)	open up (verb)
become undone or untied	make available
cause to become undone	become available
	talk freely and without inhibition
	cause to open or to become open
	become open
	open up an area or prepare a way
	start to operate or function or cause to start operating or functioning