nullify

1. V-T To nullify a legal decision or procedure means to declare that it is not legally valid. 使失去法律效力[正式]

They knew the courts could nullify the marriage before the ink was dry. 他們知道法庭可以在簽訂婚約的墨汁未干之前，宣布婚姻無效。

2. V-T To nullify something means to make it have no effect. 使無效[正式]

A missing or illegible name will nullify your vote. 遺漏或字跡難以辨認的名字會使你的投票無效。