It seems to me that a man cannot be called a villain just because he does wicked things. What is essential to being a villain is that he does his wicked things in secret. He is a bad guy who pretends to be a good guy. That is a real villain. Shakespeare created some very good villains. Claudius is one of them. He managed to murder his brother without a soul knowing about it, and then he managed to marry his dead brother's wife without Gertrude even suspecting that her new husband had killed her old one. Claudius is a "smiling villain," according to Hamlet. Right after he learns the truth from his father's ghost he says:
O villain, villain, smiling, damned villain!
My tables—meet it is I set it down
That one may smile, and smile, and be a villain;
At least I am sure it may be so in Denmark.
Edmund in King Lear is another good Shakespearean villain. He is a vicious, malevolent man, but he manages to deceive his father and his brother Edgar. Like Claudius, Edmund is clever. A villain has to be clever in order to sustain his deceit and keep from being found out.
Iago is a third memorable Shakespearean villain. He not only deceives Othello, but he deceives Desdemona, Cassio, Roderigo, and his own wife. His wife Emilia is the one who finally finds him out and exposes him to the whole world.
So the marks of a real villain are secrecy, deceit and cunning. They are able to work their evil because they can get people to trust them. There are still plenty of villains around--and they don't wear tee-shirts imprinted with the words "Watch out! I am a villain!" How do we know a guy is a villain? We don't. But we can learn a lot about how such people operate from reading Hamlet, King Lear, and Othello.
King Claudius in William Shakespeare's play "Hamlet" is a interesting character, because even though he commits evil deeds, unlike many classic stage villains, he is charming, courteous, and persuasive. Although many of his actions are unequivocally evil, he is courteous and even considerate in small matters, thus masking his villainy. He is also morally aware of his misdeeds and perfectly rational in understanding his own villainy,
Unlike Iago, for example, he does not appear to do evil out of malice or a twisted vengeful personal character, but rather single-mindedly seeks his own advantage, despite being aware of the moral ambiguity of his own position.
The reason King Claudius is considered a villain is that he does several actions that are strikingly immoral. First, he kills his own brother. Next, he marries his deceased brother's widow. After that, he hires Rosencrantz and Guildenstern to accompany his nephew Hamlet to England, carrying a letter to the English king instructing him to kill Hamlet. While the crimes of fratricide and attempted murder of his nephew, for no reason but to fulfill his own ambition, make him a villain, he is fully aware of the immorality of his actions, saying in a soliloquy:
... But, O, what form of prayer
Can serve my turn? 'Forgive me my foul murder'?
That cannot be; since I am still possess'd
Of those effects for which I did the murder,
My crown, mine own ambition and my queen.
May one be pardon'd and retain the offence?