enamel has 1 distinct synonym spread across 1 of its 5 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.
hard white substance covering the crown of a tooth
a colored glassy compound (opaque or partially opaque) that is fused to the surface of metal or glass or pottery for decoration or protection
a paint that dries to a hard glossy finish
any smooth glossy coating that resembles ceramic glaze
coat, inlay, or surface with enamel
Synonyms, antonyms and the broader and narrower relations for enamel come from Princeton University’s WordNet. Full sources and licences.