ἐκτεφρόομαι

From LSJ

σιγᾶν ἄμεινον ἢ λαλεῖν ἃ μὴ πρέπει → it's better to keep silence than to say what's not appropriate (Menander)

Source

Spanish (DGE)

reducirse a cenizas τὸ δ' ἐκτεφρωθὲν τῆς γῆς Timae.58, cf. Plu.2.696b, οὕτως γὰρ οὐκ ἐκτεφροῦται (λίβανος) Dsc.1.68.4, fig., de la bilis, Alex.Trall.1.419.23
fig. τοὺς θεωνύμους ὅλους de Luciano App.Anth.3.224.

Russian (Dvoretsky)

ἐκτεφρόομαι: превращаться в пепел Plut.