μαστιχάω
From LSJ
καὶ ἐχθροὶ τοῦ ἀνθρώπου οἱ οἰκιακοὶ αὐτοῦ → and a man's foes shall be they of his own household (Micah 7:6, Matthew 10:36)
English (LSJ)
A gnash the teeth, Ep. dat. part. μαστιχόωντι Hes.Sc. 389:—Med., gloss on μασταρίζειν, Hsch.
Greek (Liddell-Scott)
μαστῐχάω: (μάσταξ;) τρίζω τοὺς ὀδόντας, μόνον ἐν Ἡσ. Ἀσπ. Ἡρ. 389, Ἐπ. δοτ. μετοχ. μαστιχόωντι ἀντὶ μαστιχῶντι· πρβλ. μασταρύζω.