διόμνῡμι · diomnymi — LSJ
swear solemnly, declare on oath, vow, asseverate, you swore to, in the oath, on oath, swear by
swear solemnly, declare on oath, esp. in courts of justice, c. fut. inf., ὅρκον αὑτῷ προσβαλὼν διώμοσεν, ἦ μὴν . . δουλώσειν S. Tr. 255; δ. κτείνειν (κτενεῖν Cobet) Lycurg. 127:—more freq. in Med., διόμνῠμαι, fut. -ομοῦμαι: aor. -ωμοσάμην, vow, asseverate, S. Aj. 1233, Tr. 378: c. inf., Ῥωμύλον ἰδεῖν Plu. Num. 2; ζημιώσειν Id. Cam. 39: esp. of the διωμοσία (q. v.), δ. ὅρκον Antipho 5.12; ταῦτα διωμόσω ἐν τῇ ἀντιγραφῇ you swore to this in the oath you took in support of the indictment, Pl. Ap. 27