unfasten vs unbend

unfasten and unbend both are verbs.

Word	Noun	Adjective	Verb	Adverb
unfasten	No	No	Yes	No
unbend	No	No	Yes	No

As verbs, unbend is a hyponym of unfasten; that is, unbend is a word with a more specific, narrower meaning than unfasten:

Other hyponyms of unfasten include unchain, unzip.

unfasten (verb)	unbend (verb)
become undone or untied	release from mental strain, tension, or formality
cause to become undone	become less tense, rest, or take one's ease
	make less taut
	free from flexure
	unfasten, as a sail, from a spar or a stay
	straighten up or out; make straight