lethargyyoudaoicibaDictYouDict[lethargy 词源字典]
lethargy: [14] Greek léthē meant ‘oblivion’ (the Romans used it for the name of a river in Hades whose water induced forgetfulness, and its influence has also been traced in changing Latin lētum ‘death’ to lēthum, source of English lethal [17]). From it was formed the adjective léthargos, which in turn produced the noun lēthargíā, source (via Latin and Old French) of English lethargy.
=> lethal[lethargy etymology, lethargy origin, 英语词源]
lethargy (n.)youdaoicibaDictYouDict
late 14c., litarge, from Old French litargie or directly from Medieval Latin litargia, from Late Latin lethargia, from Greek lethargia "forgetfulness," from lethargos "forgetful," originally "inactive through forgetfulness," from lethe "forgetfulness" (see latent) + argos "idle" (see argon). The form with -th- is from 1590s in English.