mid-15c. (transitive), from present participle stem of Middle French ternir "dull the luster or brightness of, make dim" (15c.), probably from Old French terne (adj.) "dull, dark," which according to Diez is from a Germanic source cognate with Old High German tarnjan "to conceal, hide," Old English dyrnan "to hide, darken," from Proto-Germanic *darnjaz (see dern), but there are difficulties of form, sense, and date. Intransitive sense from 1670s. Figurative sense is from 1690s. Related: Tarnished; tarnishing.
tarnish (n.)
1713, from tarnish (v.).
中文解释
1. dark => dern "concealed, hidden, secret, dark" (dark 与 dern 同源) => tern- => tarn- + -ish.2. => dull the luster or brightness of, make dim.3. 读：踏你屎，用光泽的脚踏你的屎以后，鞋失去光泽。
实用例句
1. The tarnish lay thick on the inside of the ring.
戒指内侧有一层厚厚的锈斑。
来自柯林斯例句
2. Moisture leads to the tarnish of the silverware.
湿气使得银器毫无光泽.
来自《简明英汉词典》
3. Wear cotton gloves when cleaning silver, because the acid in your skin can tarnish the metal.
清洁银器时要戴上棉手套，因为你皮肤里的酸性物质会使它失去光泽。
来自柯林斯例句
4. The affair could tarnish the reputation of the prime minister.