lethargic

The story

1. Ancient Greek · learned borrowing fromληθαργικός
2. English todaylethargic

Learned borrowing from Ancient Greek ληθαργικός (lēthargikós), from λήθαργος (lḗthargos, “forgetful, lethargic”), from λήθη (lḗthē, “a forgetting, forgetfulness”) (from which Lethe (“river in Hades”)) + ἀργός (argós, “not working”). By surface analysis, lethargy + -ic.