Strong G20399ἐξόμνυμι

swear, make affidavit

Transliteration
exomnumi

Definition

1. to swear in excuse , (Demosthenes Orator): to swear in the negative , ἐξ. τὸ μὴ εἰδέναι (Sophocles Tragicus):—;mostly in Mid., to deny or disown upon oath, swear formally that one does not know a thing, (Demosthenes Orator), etc.
2. to decline an office by oath that one cannot perform it, (Aeschines Orator), etc. (ML)