One who violates his allegiance and betrays his country; one guilty of treason; one who, in breach of trust, delivers his country to an enemy, or yields up any fort or place intrusted to his defense, or surrenders an army or body of troops to the enemy, unless when vanquished; also, one who takes arms and levies war against his country; or one who aids an enemy in conquering his country. See Treason.
Hence, one who betrays any confidence or trust; a betrayer.
A traitor is everyone who does not agree with me. George III
A traitor is a betrayer - one who practices injury, while professing friendship. Benedict Arnold was a traitor, solely because, while professing friendship for the American cause, he attempted to injure it. An open enemy, however criminal in other respects, is no traitor. Lysander Spooner
Being called a traitor by Dick Cheney is the highest honor you can give an American, and the more panicked talk we hear from people like him... the better off we all are. Edward Snowden
The pacifist is as surely a traitor to his country and to humanity as is the most brutal wrongdoer. Theodore Roosevelt
Some say Edward Snowden is a hero and a patriot. Others say he's a fool and a traitor. The evidence is mounting that the guy who leaked the details about the National Security Agency's Internet-eavesdropping program may be something more sinister - namely, a willing tool in China's ongoing cyberwar against our nation. Arthur L. Herman