nullify

v. t. [ imp. & p. p. Nullified p. pr. & vb. n. Nullifying ] [ L. nullificare; nullus none + -ficare (in comp.) to make. See Null, a., and -fy. ] To make void; to render invalid; to deprive of legal force or efficacy. [ 1913 Webster ]

Such correspondence would at once nullify the conditions of the probationary system. I. Taylor. [ 1913 Webster ]

Syn. -- To abrogate; revoke; annul; repeal; invalidate; cancel. See Abolish. [ 1913 Webster ]