negate

verb (used with object), ne·gat·ed, ne·gat·ing.

1. to deny the existence, evidence, or truth of: an investigation tending to negate any supernatural influences.
2. to nullify or cause to be ineffective: Progress on the study has been negated by the lack of funds.

verb (used without object), ne·gat·ed, ne·gat·ing.

3. to be negative; bring or cause negative results: a pessimism that always negates.

verb (tr)

1. to make ineffective or void; nullify; invalidate
2. to deny or contradict

v.1795 (with an isolated use from 1620s), back-formation from negation, or else from Latin negatus, past participle of negare. Related: Negated; negates; negating.