tic (n.)youdaoicibaDictYouDict[tic 词源字典]
twitching of a facial muscle, 1822, often a shortening of tic douloureux "severe facial neuralgia," literally "painful twitch" (1798), from French tic "a twitching disease of horses" (17c.), of unknown origin. Klein suggests an imitative origin; Diez compare it to Italian ticchio "whim, caprice, ridiculous habit," itself of unknown origin.[tic etymology, tic origin, 英语词源]