λήθαιος
From LSJ
οὐκ ἔστι λύπης, ἄν περ ὀρθῶς τις σκοπῇ, ἄλγημα μεῖζον τῶν ἐν ἀνθρώπου φύσει → amongst the natural ills of man there is, if one but look at it aright, no greater pain than grief
English (LSJ)
or ληθαῖος, α, ον, (λήθη)
A of or causing forgetfulness, πτερόν, of Sleep, Call.Del.234; σκότος Lyc.1127, etc. 2 of persons, oblivious, opp. ἔμφρων, S.E.M.7.129. II of or from Lethe, ἄκατος AP9.279 (Bass.); v.λήθη 11. III λ. λίθος, = μελιτίτης λ., Ps.-Dsc.476 ed. Sarac.