charm has 20 distinct synonyms spread across 6 of its 8 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.
attractiveness that interests or pleases or stimulates
“his smile was part of his appeal to her”
a verbal formula believed to have magical force
“he whispered a spell as he moved his hands”
(physics) one of the six flavors of quark
protect through supernatural powers or charms
Synonyms, antonyms and the broader and narrower relations for charm come from Princeton University’s WordNet. Full sources and licences.