traitor

One who betrays one's country, a cause, or a trust, especially one who commits treason.

To act the traitor toward; betray.

One who violates his allegiance and betrays his country; one who is guilty of treason. See treason.

One who betrays any trust; a person guilty of perfidy or treachery; one who violates confidence reposed in him.

Synonyms Rebel, etc. See insurgent.