nul·li·fy/`nʌləˏfaɪ; ˈnʌlɪfaɪ/ v [T] 1law to state officially that something is not legally effective 【法律】 使无效: The Senate has voted to nullify the decree. 参议院已投票取消这条法令。 2especially BrE to make something less powerful or effective 【尤英】 抵消，削弱: Recent wage increases have been nullified by inflation. 近日的加薪已被通胀抵消。