negate
ne-gate
verb
To make something ineffective or invalid; to cancel out its effect.
"His poor performance might negate his chances of promotion."
verb
To deny the existence, truth, or validity of something.
"She tried to negate the accusations made against her."
Thesaurus
Synonyms: belie, contradict, neutralize, neutralise, nullify, contravene
Antonyms: affirm, confirm, corroborate, substantiate, support, sustain