quash /kwɒʃ $ kwɑːʃ, kwɒːʃ/ BrE AmE verb [transitive] formal
[ Sense 1: Date: 1200-1300 ; Language: Old French ; Origin: quasser , from Late Latin cassare , from Latin cassus 'having no effect, void' ]
[ Sense 2: Date: 1300-1400 ; Language: Old French ; Origin: quasser , from Latin quassare 'to shake violently, break' ]
1 . to officially say that a legal judgment or decision is no longer acceptable or correct SYN overturn :
The High Court later quashed his conviction for murder.
The decision was quashed by the House of Lords.
2 . to say or do something to stop something from continuing:
A hospital chief executive has quashed rumours that people will lose their jobs.
The government immediately moved to quash the revolt.