loosen vs straighten out

loosen and straighten out both are verbs.

Word	Noun	Adjective	Verb	Adverb
loosen	No	No	Yes	No
straighten out	No	No	Yes	No

As verbs, straighten out is a hypernym of loosen; that is, straighten out is a word with a broader meaning than loosen:

Other hypernyms of loosen include disentangle, unsnarl.

loosen (verb)	straighten out (verb)
become loose or looser or less tight	put (things or places) in order
make loose or looser	settle or put right
make less dense	change for the better
disentangle and raise the fibers of	make free from confusion or ambiguity; make clear
cause to become loose	make straight
become less severe or strict	extricate from entanglement
make less severe or strict