traitor
n. countablen. someone who is not loyal to their country, friends, or a group. You use this word for a person who helps an enemy or breaks a serious promise.
n. a person who betrays a friend, country, principle, or cause. Often carries a strong moral or legal condemnation, implying a breach of trust or allegiance.
He was called a traitor for joining the rival team.
The general was executed after he was found to be a traitor who sold secrets to the enemy.
History often reframes the figure of the traitor, as those once branded as such by a falling regime are frequently celebrated as heroes by the succeeding one.
From Middle English traitor, traitour, traytour, from Old French traïtor (French traître), from Latin trāditor. Displaced native Middle English swike from Old English swica (“traitor”), and Middle English proditour and traditour borrowed directly from Latin. The general Old English word denoting "traitor" was lǣwa or lǣwend. Doublet of traditor.
Commonly paired with the preposition 'to' to indicate the entity betrayed.
He was a traitor of his countryHe was a traitor to his countryThe noun 'traitor' typically takes the preposition 'to' rather than 'of' when identifying the victim of the betrayal.