δεκάμνως

From LSJ

δὶς ἐξαμαρτεῖν ταὐτὸν οὐκ ἀνδρὸς σοφοῦ → a wise man should not keep making the same mistake, a wise man should not repeat the same mistake, doing twice the same mistake is not a wise man's doing, making the same mistake twice does not befit the wise, making the same mistake twice does not belong to a man who is wise, making the same mistake twice does not belong to a wise man, the wise man does not make the same mistake twice, to commit the same sin twice is not a sign of a wise man, it is unwise to err twice

Source

Greek (Liddell-Scott)

δεκάμνως: μνων, (μνᾶ)· - ὁ ζυγίζων ἢ ἀξίζων δέκα μνᾶς, Ἀριστοφ. Εἰρ. 1224, 1235· δεκάμνουν, τό, βάρος δέκα μνῶν, Συλλ. Ἐπιγρ. 123, 8.