to say officially that something, especially an earlier official decision, is no longer to be accepted撤銷,廢止,宣布…無效
His conviction was quashed in March 1986 after his counsel argued that the police evidence was all lies.他的辯護人舉證說明了警方的證據是一派謊言,於是對他的判決於1986年3月被撤銷了。