straighten vs straighten out

straighten and straighten out both are verbs.

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

As verbs, straighten and straighten out are synonyms defined as:

Other synonyms of straighten include clean up, neaten, square away, tidy, tidy up.

As verbs, straighten and straighten out are synonyms defined as:

straighten (verb)	straighten out (verb)
put (things or places) in order	put (things or places) in order
make straight or straighter	settle or put right
make straight	change for the better
straighten by unrolling	make free from confusion or ambiguity; make clear
straighten up or out; make straight	make straight
get up from a sitting or slouching position	extricate from entanglement