contradiction

n. denial; opposition; inconsistency

In logic, a contradiction consists of a logical incompatibility between two or more propositions. It occurs when the propositions, taken together, yield two conclusions which form the logical inversions of each other. Illustrating a general tendency in applied logic, Aristotle’s law of noncontradiction states that “One cannot say of something that it is and that it is not in the same respect and at the same time.”
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Noun
1. opposition between two conflicting forces or ideas
(hypernym) opposition, oppositeness
(hyponym) dialectic
2. (logic) a statement that is necessarily false; "the statement `he is brave and he is not brave' is a contradiction"
(synonym) contradiction in terms
(hypernym) falsehood, falsity, untruth, false statement
(hyponym) antinomy
(classification) logic
3. the speech act of contradicting someone; "he spoke as if he thought his claims were immune to contradiction"
(hypernym) negation
(derivation) contradict, negate, contravene

n. contradiction; discrepancy, conflict; poles apart

(n.)
Direct opposition or repugnancy; inconsistency; incongruity or contrariety; one who, or that which, is inconsistent.
  

(n.)
An assertion of the contrary to what has been said or affirmed; denial of the truth of a statement or assertion; contrary declaration; gainsaying.