Definition of negation noun from the Oxford Advanced Learner's Dictionary
negation
noun
nɪˈɡeɪʃn nɪˈɡeɪʃn
(formal)
1[countable, usually singular, uncountable]the exact opposite of something; the act of causing something not to exist or to become its oppositeThis political system was the negation of democracy.2[uncountable]disagreement or refusalShe shook her head in negation.