annul/əˈnʌl; ə`nʌl/ v[Tn](-ll-) declare (sth) no longer valid; abolish; cancel 宣告（某事物）无效; 废止; 取消 annul an agreement/a contract/a law/a marriage 宣告协议[合同/法令/婚姻]无效.
牛津英汉双解词典