mitchell has 9 distinct synonyms spread across 6 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.
English aeronautical engineer (1895-1937)
United States aviator and general who was an early advocate of military air power (1879-1936)
United States astronomer who studied sunspots and nebulae (1818-1889)
United States writer noted for her novel about the South during the American Civil War (1900-1949)
United States labor leader; president of the United Mine Workers of America from 1898 to 1908 (1870-1919)
United States dancer who formed the first Black classical ballet company (born in 1934)
Synonyms, antonyms and the broader and narrower relations for mitchell come from Princeton University’s WordNet. Full sources and licences.