Stories We Like: Novels For Language Lovers
1590s, 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," 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). Figurative sense is from 1690s. Related: Tarnished; tarnishing.
1713, from tarnish (v.).