the act of denying

He shook his head in negation of the charge.

a denial

a negation of one's former beliefs.

something that is without existence; nonentity.

the absence or opposite of something that is actual, positive, or affirmative

Darkness is the negation of light.

a negative statement, idea, concept, doctrine, etc.; a contradiction, refutation, or rebuttal

a shameless lie that demands a negation.

noun

allowance , approval , permission

noun

antithesis , antonym , blank , cancellation , contrary , converse , counterpart , disavowal , disclaimer , forget it , gainsaying , inverse , negatory , neutralization , no , nonexistence , nothingness , nullification , nullity , opposite , opposition , proscription , refusal , rejection , renunciation , repudiation , reverse , vacuity , veto , void , abolishment , abrogation , annihilation , annulment , defeasance , invalidation , voidance , contradiction , disaffirmance , disaffirmation