nullify (nullifies 3rd person present) (nullifying present participle) (nullified past tense & past participle )
1 verb To nullify a legal decision or procedure means to declare that it is not legally valid.
FORMAL
(=invalidate)
He used his broad executive powers to nullify decisions by local governments... V n
2 verb To nullify something means to make it have no effect.
FORMAL
(=negate)
He may be able to nullify that disadvantage by offering a wider variety of produce... V n