In law, treason is the crime of disloyalty to one's nation or state. A person who betrays the nation of their citizenship and/or reneges on an oath of loyalty and in some way willfully cooperates with an enemy, is considered to be a traitor. Oran's Dictionary of the Law (1983) defines treason as: "...[a]...citizen's actions to help a foreign government overthrow, make war against, or seriously injure the [parent nation]." In many nations, it is also often considered treason to attempt or conspire to overthrow the government, even if no foreign country is aided or involved by such an endeavour.
Traitor may also mean a person who betrays (or is accused of betraying) their own political party, family, friends, ethnic group, religion, or other group to which they may belong. Often, such accusations are controversial and disputed, as the person may not identify with the group of which they are a member, or may otherwise disagree with the group leaders making the charge. See, for example, race traitor.
At times, the term "traitor" has been levelled as a political epithet, regardless of any verifiable treasonous action. In a civil war or insurrection, the winners may deem the losers to be traitors. Likewise the term "traitor" is used in heated political discussion – typically as a slur against political dissidents, or against officials in power who are perceived as failing to act in the best interest of their constituents. In certain cases, as with the German Dolchstoßlegende, the accusation of treason towards a large group of people can be a unifying political message.
Figures in history who are renowned for acts of treachery have subsequently had their names become synonymous with the word "traitor". Some examples are Benedict Arnold, Pétain, Quisling, and Ephialtes.
