What is the meaning of quash?

verb

• Put down by force or intimidation.
  • usage: "The government quashes any attempt of an uprising"; "China keeps down her dissidents very efficiently"; "The rich landowners subjugated the peasants working the land"
  • synonyms: repress, keep down, subdue, subjugate, reduce
• Declare invalid.
  • usage: "The contract was annulled"; "void a plea"
  • synonyms: invalidate, annul, void, avoid, nullify