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)