nullify-v; 1 Senses

Sense Number 1: Declare or show to be invalid; cause to not exist

Their actions nullified the contract.
The plea was nullified.
Her optimism helps to nullify the effect of his gloom on the organization.
The action will nullify the effect of my efforts.

VerbNet: void-106
FrameNet: NP
PropBank: nullify.01
WordNet 3.0 Sense Numbers: 1, 2, 3