Webster’s Revised Unabridged Dictionary · 1913
Nullify
Nul′li·fy, 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.
Such correspondence would at once nullify the conditions of the probationary system. I. Taylor.
Syn. — To abrogate; revoke; annul; repeal; invalidate; cancel. See Abolish.