facilis descensus AverniyoudaoicibaDictYouDict[facilis descensus Averni 词源字典]
Latin, literally "the descent of Avernus (is) easy" ["Aeneid," VI.126], in reference to Avernus, a deep lake near Puteoli and a reputed entrance to the underworld; hence, "it is easy to slip into moral ruin."[facilis descensus Averni etymology, facilis descensus Averni origin, 英语词源]