MEDEA: I think the unjust man who can speak cleverly
incurs the greatest penalty for, feeling confident
to cloak injustice in fair speech,
he dares the utmost villainy.

[ΜΉΔΕΙΑ: ἐμοὶ γὰρ ὅστις ἄδικος ὢν σοφὸς λέγειν
πέφυκε, πλείστην ζημίαν ὀφλισκάνει:
γλώσσῃ γὰρ αὐχῶν τἄδικ᾽ εὖ περιστελεῖν
τολμᾷ πανουργεῖν.]

Euripides (485?-406? BC) Greek tragic dramatist

Medea [Μήδεια], l. 580ff (431 BC) [tr. Ewans (2022)]
    (Source)

(Source (Greek)). Other translations:

In my judgement, he
Who tramples on the laws, but can express
His thoughts with plausibility, deserves
Severest punishment: for that injustice
On which he glories, with his artful tongue.
That he a fair appearance can bestow,
He dares to practise.
[tr. Wodhull (1782)]

Th' injurious man, whose tongue
Flows with pernicious rhetoric, I hold
To merit the severest punishment.
For confident his speech can varnish o'er
The blackest deeds, his craft dares venture on them.
[tr. Potter (1814)]

For him who does wrong and is wise to gloze it
I hold worth worser doom. For making sure
He'll show wrong gracious with his tongue, he's bold
To every crime.
[tr. Webster (1868)]

To my mind, whoso hath skill to fence with words in an unjust cause, incurs the heaviest penalty; for such an one, confident that he can cast a decent veil of words o'er his injustice, dares to practise it.
[tr. Coleridge (1891)]

In my judgment, whatever man being unjust, is deeply skilled in argument, merits the severest punishment. For vaunting that with his tongue he can well gloze over injustice, he dares to work deceit.
[tr. Buckley (1892)]

For in my sight the villain subtle-tongued
Getteth himself for gain exceeding loss,
Who, confident his tongue can gloze the wrong,
Becomes a bold knave.
[tr. Way (Loeb) (1894)]

To me it seemeth, when
A crafty tongue is given to evil men
'Tis like to wreck, not help them. Their own brain
Tempts them with lies to dare and dare again,
Till .... [tr. Murray (1906)]

I think that the plausible speaker
Who is a villain deserves the greatest punishment.
Confident in his tongue’s power to adorn evil,
He stops at nothing.
[tr. Warner (1944)]

To me, a wicked man who is also eloquent
Seems the most guilty of them all. He’ll cut your throat
As bold as brass, because he knows he can dress up murder
In handsome words.
[tr. Vellacott (1963)]

For me, the man who is a villain, but clever
In speech, would have to pay the highest fine;
Confident of cloaking his villainy in fine words,
He dares anything.
[tr. Podlecki (1989)]

To my mind, the plausible speaker who is a scoundrel incurs the greatest punishment. For since he is confident that he can cleverly cloak injustice with his words, his boldness stops at no knavery.
[tr. Kovacs (Loeb) (1994)]

For in my eyes the criminal with a gift for speaking deserves the worst of punishments. So confident is he in his tongue’s ability to dress his foul thoughts in fair words, there is nothing he dares not do.
[tr. Davie (1996)]

What I believe, for example is the more eloquent the misfit, the greater the punishment he deserves because, thinking that his eloquence and his pretty words will get him out of any injustice, he has the audacity to commit even greater evils.
[tr. Theodoridis (2004)]

In my opinion,
the unjust man who speaks so plausibly
brings on himself the harshest punishment.
Since he’s sure his tongue can hide injustice,
he dares anything.
[tr. Johnston (2008), l. 689ff]

To my mind, whoever is naturally sophos in speaking but has no dikē deserves the heaviest punishment. Such a man boasts that he can cast a decent veil of words over his unjust deeds, and boldly proceeds to wickedness.
[tr. Coleridge / Ceragioli / Nagy / Hour25]

To my mind, the plausible speaker who is a scoundrel incurs the greatest punishment. For since he is confident that he can cleverly cloak injustice with his words, his boldness stops at no dishonesty.
[tr. Kovacs / Zhang / Rogak]