tedious (adj.)youdaoicibaDictYouDict[tedious 词源字典]
early 15c., from Old French tedieus, from Late Latin taediosus "wearisome, irksome, tedious," from Latin taedium (see tedium). Related: Tediously; tediousness.[tedious etymology, tedious origin, 英语词源]
tedium (n.)youdaoicibaDictYouDict
"tediousness," 1660s, from Latin taedium "weariness, irksomeness, disgust," related to taedet "it is wearisome, it excites loathing," and to taedere "to weary," of uncertain origin. Possible cognates are Old Church Slavonic težo, Lithuanian tingiu "to be dull, be listless."