Aristotle, Nicomachean Ethics
4.7.2-6 (1127 a 21-32; tr. Benjamin Jowett, rev. Jonathan Barnes):
The boastful man, then, is thought to be apt to claim the things that bring glory, when he has not got them, or to claim more of them than he has, and the mock-modest man on the other hand to disclaim what he has or belittle it, while the man who observes the mean is one who calls a thing by its own name, being truthful both in life and in word, owning to what he has, and neither more nor less. Now each of these courses may be adopted either with or without an object. But each man speaks and acts and lives in accordance with his character, if he is not acting for some ulterior object. And falsehood is in itself mean and culpable, and truth noble and worthy of praise. Thus the truthful man is another case of a man who, being in the mean, is worthy of praise, and both forms of untruthful man are culpable, and particularly the boastful man.
δοκεῖ δὴ ὁ μὲν ἀλαζὼν προσποιητικὸς τῶν ἐνδόξων εἶναι καὶ μὴ ὑπαρχόντων καὶ μειζόνων ἢ ὑπάρχει, ὁ δὲ εἴρων ἀνάπαλιν ἀρνεῖσθαι τὰ ὑπάρχοντα ἢ ἐλάττω ποιεῖν, ὁ δὲ μέσος αὐθέκαστός τις ὢν ἀληθευτικὸς κἂν τῷ βίῳ καὶ τῷ λόγῳ, τὰ ὑπάρχοντα ὁμολογῶν εἶναι περὶ αὑτόν, καὶ οὔτε μείζω οὔτε ἐλάττω. ἔστι δὲ τούτων ἕκαστα καὶ ἕνεκά τινος ποιεῖν καὶ μηθενός· ἕκαστος δ᾿ οἷός ἐστι, τοιαῦτα λέγει καὶ πράττει καὶ οὕτω ζῇ, ἐὰν μή τινος ἕνεκα πράττῃ. καθ᾿ αὑτὸ δὲ τὸ μὲν ψεῦδος φαῦλον καὶ ψεκτόν, τὸ δ᾿ ἀληθὲς καλὸν καὶ ἐπαινετόν· οὕτω δὲ καὶ ὁ μὲν ἀληθευτικὸς μέσος ὢν ἐπαινετός, οἱ δὲ ψευδόμενοι ἀμφότεροι μὲν ψεκτοί, μᾶλλον δ᾿ ὁ ἀλαζών.