What is the meaning of clear up?

verb

• Make clear and (more) comprehensible.
  • usage: "clarify the mystery surrounding her death"
  • synonyms: clarify, elucidate
• Finish a task completely.
  • usage: "I finally got through this homework assignment"
  • synonyms: get through, wrap up, finish off, mop up, polish off, finish up
• Free (the throat) by making a rasping sound.
  • usage: "Clear the throat"
  • synonyms: clear
• Become clear.
  • usage: "The sky cleared after the storm"
  • synonyms: clear, light up, brighten
• Make free from confusion or ambiguity; make clear.
  • usage: "Could you clarify these remarks"; "Clear up the question of who is at fault"
  • synonyms: clear, shed light on, crystallize, crystallise, crystalize, crystalise, straighten out, sort out, enlighten, illuminate, elucidate