ἀρρητολογία
From LSJ
ἔστιν δέ που ἡ μὲν ἐπὶ σώμασι γυμναστική, ἡ δ' ἐπὶ ψυχῇ μουσική → I think I am right in saying that we have physical exercise for the body and the arts for the soul
Greek (Liddell-Scott)
ἀρρητολογία: ἡ βέβηλος, ἀνίερος ὁμιλία, Εὐσεβ. Εὐαγγ. Πρ. 3. 13, σ. 122Α.
Spanish (DGE)
-ας, ἡ lenguaje inexplicable Eus.PE 3.13.19, 5.32.2.