concede has 5 distinct synonyms spread across 3 of its 4 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.
admit (to a wrongdoing)
“She confessed that she had taken the money”
be willing to concede
“I grant you this much”
Synonyms, antonyms and the broader and narrower relations for concede come from Princeton University’s WordNet. Full sources and licences.
acknowledge defeat
“The candidate conceded after enough votes had come in to show that he would lose”