(nullifies, nullifying, nullified)
1.
To nullify a legal decision or procedure means to declare that it is not legally valid. (FORMAL)
He used his broad executive powers to nullify decisions by local governments...
It is worth remembering that previous wills are nullified automatically upon marriage.
= invalidate
VERB: V n, V n
2.
To nullify something means to make it have no effect. (FORMAL)
He may be able to nullify that disadvantage by offering a wider variety of produce...
= negate
VERB: V n