1. (verb)repress, quash, keep down, subdue, subjugate, reduce put down by force or intimidation "The government quashes any attempt of an uprising"; "China keeps down her dissidents very efficiently"; "The rich landowners subjugated the peasants working the land"
2. (verb)invalidate, annul, quash, void, avoid, nullify declare invalid "The contract was annulled"; "void a plea"