NULLIFY
neutralize, neutralise, nullify, negate
(verb) make ineffective by counterbalancing the effect of; “Her optimism neutralizes his gloom”; “This action will negate the effect of my efforts”
invalidate, nullify
(verb) show to be invalid
invalidate, annul, quash, void, avoid, nullify
(verb) declare invalid; “The contract was annulled”; “void a plea”
Source: WordNet® 3.1
Etymology
Verb
nullify (third-person singular simple present nullifies, present participle nullifying, simple past and past participle nullified)
(transitive, legal) to make legally invalid.
to prevent from happening
Synonyms
• (to make legally invalid): annul, cancel
Source: Wiktionary
Nul"li*fy, v. t. [imp. & p. p. Nullified; p. pr. & vb. n.
Nullifying.] Etym: [L. nullificare; nullus none + -ficare (in comp.)
to make. See Null, a., and -fy.]
Definition: 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.
Source: Webster’s Unabridged Dictionary 1913 Edition