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. 他们知道法庭可以在签订婚约的墨汁未干之前，宣布婚姻无效。

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

A missing or illegible name will nullify your vote. 遗漏或字迹难以辨认的名字会使你的投票无效。