ματαιόφωνος
From LSJ
τί δὲ βλέπεις τὸ κάρφος τὸ ἐν τῷ ὀφθαλμῷ τοῦ ἀδελφοῦ σου, τὴν δὲ ἐν τῷ σῷ ὀφθαλμῷ δοκὸν οὐ κατανοεῖς → why do you look at the speck of sawdust in your brother's eye and pay no attention to the plank in your own eye | and why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye | why do you see the speck that is in your brother's eye, but don't consider the beam that is in your own eye
English (LSJ)
ματαιόφωνον, talking idly, Hsch. s.v. μαψίφωνος.
Greek (Liddell-Scott)
μᾰταιόφωνος: -ον, ὁ ματαίως, ἀφρόνως ὁμιλῶν, ὁ μάταια φωνῶν, Ἡσύχ. ἐν λέξ. μαψίφωνος· ― οὐσιαστ. ματαιοφωνία, ἡ Σουΐδ. ἐν λέξ. κενοφωνία, Φώτ.
Greek Monolingual
ματαιόφωνος, -ον (Α)
αυτός που μιλάει ανόητα και άσκοπα.
[ΕΤΥΜΟΛ. < μάταιος + -φωνος (< φωνή), πρβλ. υψηλόφωνος].