1. [ verb ] show to be invalid
Synonyms: invalidate
Related terms: validate negate
2. [ verb ] (law) declare invalid
Synonyms: invalidate void quash avoid annul

"The contract was annulled" "avoid a plea"

Related terms: validate cancel break stet nullifier invalidator nothingness annulment
3. [ verb ] make ineffective by counterbalancing the effect of
Synonyms: neutralize neutralise negate

"Her optimism neutralizes his gloom" "This action will negate the effect of my efforts"

Related terms: weaken nullification
Similar spelling:   Nulph