ἐθελοντηδόν
From LSJ
Ἀναξαγόρας δύο ἔλεγε διδασκαλίας εἶναι θανάτου, τόν τε πρὸ τοῦ γενέσθαι χρόνον καὶ τὸν ὕπνον → Anaxagoras used to say that we have two teachers for death: the time before we were born and sleep | Anaxagoras said that there are two rehearsals for death: the time before being born and sleep
English (LSJ)
Adv.
A voluntarily, spontaneously, Th.8.98, D.C.53.8; f.l. for sq., Plb.6.31.2.
German (Pape)
[Seite 718] freiwillig, von freien Stücken, Thuc. 8, 98 u. Folgde, wie D. C. 53, 8.
Greek (Liddell-Scott)
ἐθελοντηδόν: ἐπίρρ., ἑκουσίως, Θουκ. 8. 9, Πολύβ. 6. 31, 2.