betrayal

American  

[bih-trey-uhl] / bɪˈtreɪ əl /

noun

1. the act of exposing or delivering someone to an enemy through treachery or disloyalty.

   This security leak was an inexcusable betrayal of an ally whose very existence is now threatened.

2. the act of disappointing a person’s trust, hopes, or expectations.

   Imagine what a betrayal it is each time a rape victim finds out that her fellow citizens, and our legal system, are just not there for her.

3. the act of revealing information in violation of confidence.

   The library, which carried books criticizing the regime, was kept in private homes and frequently had to be moved to avoid betrayal of its secret to the local authorities.

4. failure to keep or honor a promise, principle, cherished memory, etc..

   Many of his constituents are unhappy with his promotion of new mining and logging initiatives, seeing it as a betrayal of his green ideals.

5. an act or instance of unconsciously revealing or displaying some quality or characteristic, typically one preferably concealed.

   A slight tremor in her hand was the only betrayal of her fear.

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Usage

What does betrayal mean? Betrayal is when someone you trust breaks that trust by doing something that hurts you. This can take many forms, such as a soldier working with the enemy, one family member stealing from another, or a friend spreading rumors about another friend. Betrayal is the noun form of the verb betray, which means to be disloyal or traitorous. A specific act of disloyalty is a betrayal, as in The businessman never forgave his partner’s betrayal of joining his hated rival’s company. Betrayal is also used to describe how you reveal something unconsciously, like how a blush betrays embarrassment. An act is only considered a betrayal if it violates an existing trust. The word typically implies a serious violation of trust that causes serious harm. Example: The knights’ betrayal of their king helped the invaders win the war.

Other Word Forms

• prebetrayal
  noun
• self-betrayal
  noun

Etymology

Origin of betrayal

betray ( def. ) + -al ² ( def. )

Explanation

Betrayal means "an act of deliberate disloyalty," like when your friend told other people all your secrets. What a betrayal! Betrayal's root is betray, which comes from the Middle English word bitrayen — meaning "mislead, deceive." Betrayal has to do with destroying someone's trust, possibly by lying. If you start dating your best friend's girlfriend behind his back, that's an act of betrayal. Betrayal can also mean "helping an enemy," such as a person who gives secret information to a country that is at war with his or her own.

Example Sentences

His book about the Afghan war, “Twenty Years: Hope, War and the Betrayal of an Afghan Generation,” won a 2025 Overseas Press Club Award for best nonfiction book.

From The Wall Street Journal • Jan. 17, 2026

Betrayal, they argue, from both of Westminster's big beasts.

From BBC • May 2, 2025

The show is based on the bestselling book “Capote’s Women: A True Story of Love, Betrayal, and a Swan Song for an Era,” by Laurence Leamer.

From Seattle Times • Feb. 8, 2024

“The Sand Creek Massacre: The Betrayal That Changed Cheyenne and Arapaho People Forever,” finally opened on Nov. 19, 2022, nearly 158 years after the massacre.

From New York Times • Oct. 18, 2023

Betrayal bent me in one direction while guilt bent her the other way.

From "The Poisonwood Bible" by Barbara Kingsolver

Related Words

• deception
• dishonesty
• sellout
• treachery
• treason