What is the meaning of overturn?

noun

• The act of upsetting something.
  • usage: "he was badly bruised by the upset of his sled at a high speed"
  • synonyms: upset, turnover
• An improbable and unexpected victory.
  • usage: "the biggest upset since David beat Goliath"
  • synonyms: upset

verb

• Turn from an upright or normal position.
  • usage: "The big vase overturned"; "The canoe tumped over"
  • synonyms: turn over, tip over, tump over
• Cause to overturn from an upright or normal position.
  • usage: "The cat knocked over the flower vase"; "the clumsy customer turned over the vase"; "he tumped over his beer"
  • synonyms: tip over, turn over, upset, knock over, bowl over, tump over
• Rule against.
  • usage: "The Republicans were overruled when the House voted on the bill"
  • synonyms: overrule, override, overthrow, reverse
• Cause the downfall of; of rulers.
  • usage: "The Czar was overthrown"; "subvert the ruling class"
  • synonyms: overthrow, subvert, bring down
• Cancel officially.
  • usage: "He revoked the ban on smoking"; "lift an embargo"; "vacate a death sentence"
  • synonyms: revoke, annul, lift, countermand, reverse, repeal, rescind, vacate
• Change radically.
  • usage: "E-mail revolutionized communication in academe"
  • synonyms: revolutionize, revolutionise