ὁρκοῦν
From LSJ
διὰ λαμπροτάτου βαίνοντες ἁβρῶς αἰθέρος → passing lightly through clear-shining air (Euripides, Medea 829)
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.