English Reference
noun

traitor

n.
US /ˈtɹeɪtɝ/ UK /tɹˈeɪtɐ/ traitor UK spelling traitor's, traitor's

  1. 01 B2 Upper Intermediate Law

    someone who helps an enemy of their own country or gives away national secrets.

    a person who violates an allegiance to their state or sovereign by aiding an enemy or committing treason.

    Simple

    The soldier was caught selling secret documents and was branded a traitor to his country.

    In context

    History remembers him as a traitor who provided the invading forces with the exact coordinates of the coastal defences.

    turncoatrenegadebetrayer
  2. 02 B2 Upper Intermediate Informal

    someone who is not loyal to their friends or a group they belong to.

    one who betrays a personal confidence, a shared cause, or a social group.

    Simple

    My friends called me a traitor because I started supporting the rival football team.

    In context

    In the cutthroat world of corporate politics, he was viewed as a traitor for leaking the merger details to the press.

    backstabberdouble crosser

Not after they called me a traitor to my own country.

The Guardian· 8 Sept 2026

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.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin trāditor
Level B2 · Upper Intermediate
Frequency Frequent
Updated