straighten out

1.  Clear up disorder, a confusion, or a misunderstanding, as in This is an awful mess; I hope you'll straighten it out, or I don't understand; please straighten me out. [Late 1800s]
2.  Adopt an honest, upright course, as in He's only sixteen; I'm sure he'll straighten out before long. [First half of 1900s]

The verb has 6 meanings:

Meaning #1: settle or put right; of difficulties or problems
  Synonyms: iron out, put right

Meaning #2: extricate from entanglement
  Synonyms: disentangle, unsnarl

Meaning #3: change for the better
  Synonyms: reform, see the light

Meaning #4: make straight
  Synonym: straighten

Meaning #5: make free from confusion or ambiguity; make clear
  Synonyms: clear, clear up, shed light on, crystallize, crystallise, crystalize, crystalise, sort out, enlighten, illuminate, elucidate

Meaning #6: put (things or places) in order
  Synonyms: tidy, tidy up, clean up, neaten, straighten, square away