νεφούμαι

From LSJ

Βίων δύο ἔλεγε διδασκαλίας εἶναι θανάτου, τόν τε πρὸ τοῦ γενέσθαι χρόνον καὶ τὸν ὕπνονBion used to say that we have two teachers for death: the time before we were born and sleep | Bion said that there are two rehearsals for death: the time before being born and sleep

Source

Greek Monolingual

νεφοῦμαι, -όομαι (Α) νέφος
1. (για τον ουρανό ή για τον ορίζοντα) καλύπτομαι από σύννεφα, συννεφιάζω
2. μτφ. είμαι ή καθίσταμαι ασαφής, σκοτεινός.