loosen vs unbend

loosen and unbend both are verbs.

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

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

Other hyponyms of loosen include relax, remit, slacken, slack, unscrew, unscrew.

loosen (verb)	unbend (verb)
become loose or looser or less tight	release from mental strain, tension, or formality
make loose or looser	become less tense, rest, or take one's ease
make less dense	make less taut
disentangle and raise the fibers of	free from flexure
cause to become loose	unfasten, as a sail, from a spar or a stay
become less severe or strict	straighten up or out; make straight
make less severe or strict