tidy vs straighten out

tidy is a noun but straighten out is not a noun.

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

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

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

tidy (noun)	straighten out (noun)
receptacle that holds odds and ends (as sewing materials)

tidy (adjective)	straighten out (adjective)
marked by order and cleanliness in appearance or habits
large in amount or extent or degree
(of hair) neat and tidy

tidy (verb)	straighten out (verb)
put (things or places) in order	put (things or places) in order
	settle or put right
	change for the better
	make free from confusion or ambiguity; make clear
	make straight
	extricate from entanglement