ὁρκοῦν
From LSJ
τίς δ' οἶδεν εἰ τὸ ζῆν μέν ἐστι κατθανεῖν, τὸ κατθανεῖν δὲ ζῆν κάτω νομίζεται → who knows if life is death, and if in the underworld death is considered life
Greek > English (Woodhouse Verbs Reversed)
(see also: ὁρκόω) bind, bind by an oath, bind by oath, swear in
Lexicon Thucydideum
iureiurando obstringere, to bind by an oath, 4.74.2, 8.75.2.