nullify

verbs

declare invalid
"The contract was annulled"; "void a plea"
annul, avoid, invalidate, nullify, quash, void
is derived from
nullifier
is derived from
nullification
is derived from
nullification
is derived from
nullifier
show to be invalid
invalidate, nullify
make ineffective by counterbalancing the effect of
"Her optimism neutralizes his gloom"; "This action will negate the effect of my efforts"
negate, neutralise, neutralize, nullify
is derived from
nullification