accord has 13 distinct synonyms spread across 5 of its 6 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.
harmony of people's opinions or actions or characters
“the two parties were in agreement”
concurrence of opinion
“we are in accord with your proposal”
a written agreement between two states or sovereigns
Synonyms, antonyms and the broader and narrower relations for accord come from Princeton University’s WordNet. Full sources and licences.