contradiction has 1 distinct synonym spread across 1 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
opposition between two conflicting forces or ideas
(logic) a statement that is necessarily false
“the statement `he is brave and he is not brave' is a contradiction”
the speech act of contradicting someone
“he spoke as if he thought his claims were immune to contradiction”
Synonyms, antonyms and the broader and narrower relations for contradiction come from Princeton University’s WordNet. Full sources and licences.