Verbs

(v)contradict, belie, negatebe in contradiction with
(v)contradict, negate, contravenedeny the truth of
(v)negate, contradictprove negative; show to be false
(v)neutralize, neutralise, nullify, negatemake ineffective by counterbalancing the effect of“Her optimism neutralizes his gloom”, “This action will negate the effect of my efforts”