judas
n. countablen. a person who acts like a friend but then betrays you. It comes from a story in the Bible about a man who gave his friend to his enemies.
n. a person who betrays a friend, colleague, or cause; a traitor. Derived from the biblical figure Judas Iscariot.
He felt like a judas after telling his friend's secret to the boss.
The political party struggled to recover after a high-ranking member acted as a judas by leaking private documents to the press.
In the high-stakes world of corporate espionage, one must always be wary of a potential judas within the inner circle who might sell proprietary data to a competitor.
From Middle English Iudas, from Latin Iudas, from Ancient Greek Ἰούδας (Ioúdas), from Hebrew יְהוּדָה (y'hudá). Doublet of Judah.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Often used with the indefinite article ('a judas') or as a direct label for a traitor.
Last updated May 6, 2026