κατόμνῡμι · katomnymi — LSJ
confirm by oath, τινί τι Ar. Av. 444.
c. acc., call to witness, swear by, τὴν ἐμὴν ψυχήν E. Or. 1517 (troch.), etc.; κ. τὼ θεώ Ar. Ec. 158: c. dupl. acc., ἁγνὸν ὅρκον σὸν κάρα κατώμοσα E. Hel. l.c.: c. gen., κ. τῆς κεφαλῆς Anon. ap. Suid.
swear, c. inf., IG 12(9).1273.1 (Eretria, vi B.C.).
Med. = Act., tender an oath, Antipho Soph. Oxy. 1364.140, Arist. Rh. 1377a16, PMagd. 26.13 (iii B.C.); swear by, τοὺς θεούς Aristaenet. 2.20: c. acc. et inf., D. 39.4, cf. Paus. 6.18.3.
c. dat., take an oath against, accuse on oath, Hdt. 6.65 (gen. as v.l.): abs., ib. 69.