Negate

google

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early 17th century (in negate (sense 1, sense 3)): from Latin negat- ‘denied’, from the verb negare .

wiktionary

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Borrowed from Latin negātus, past participle of negāre(“to deny, refuse, decline”), reduced from *nec-aiare (or a similar form), from nec(“not, nor”) + aiere(“to say”).

etymonline

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negate (v.)

"deny, make negative or null," 1795 (with an isolated use from 1620s), a back-formation from negation, or else from Latin negatus, past participle of negare, from PIE root *ne- "not." Related: Negated; negates; negating.