Definition of betray in English:

betray

Syllabification: be·tray
Pronunciation: /bəˈtrā
 
/

verb

[with object]
1Expose (one’s country, a group, or a person) to danger by treacherously giving information to an enemy: a double agent who betrayed some 400 British and French agents to the Germans
More example sentences
  • After all, they were betraying the organization that he had long worked to make greater.
  • I suppose often I fall over my own drawn line, but I have to give some help or I would be betraying another ethic… that of being a teacher.
  • Control Room gives insight into the concept of journalistic integrity and how each side may see the other betraying that ethic.
1.1Treacherously reveal (secrets or information): many of those employed by diplomats betrayed secrets and sold classified documents
More example sentences
  • However, sources close to him say they believe the government alleged that he was betraying details of planned NATO airstrikes to the opposition leadership.
  • I trusted Aunt Demeter to look out for my safety, but she betrayed every detail of my running away.
  • Artie promises not to betray certain details only to show us both the promise and betrayal together.
Synonyms
unmask, expose, bring out into the open;
let slip, let out, let drop, blurt out
1.2Be disloyal to: his friends were shocked when he betrayed them
More example sentences
  • And if someone is disloyal, if someone betrays a trust, in Texas, they're right down there with child molesters and ax murderers.
  • As she said, ‘I felt shocked, angry, betrayed and violated’.
  • Beat your child; and the worst part of the hurt are the feelings of love betrayed, or trust shocked.
Synonyms
be disloyal to, be unfaithful to, double-cross, cross, break faith with, inform on/against, give away, denounce, sell out, stab in the back, break one's promise to
informal rat on, fink on, sell down the river, squeal on, rat on/out, finger
2Unintentionally reveal; be evidence of: she drew a deep breath that betrayed her indignation
More example sentences
  • Neyl wriggled out of the window and held on tightly with both hands, his face betraying his shock.
  • Michael's hand fell, his face betrayed the shock he felt.
  • Katherine's face betrayed utter shock, then utter amusement.

Origin

Middle English: from be- 'thoroughly' + obsolete tray 'betray', from Old French trair, based on Latin tradere 'hand over'. Compare with traitor.

Derivatives

betrayal

noun
More example sentences
  • As a father himself he finds such disloyalty and betrayal completely unacceptable.
  • The cocaine trade being so lucrative, it encouraged disloyalty and betrayal.
  • Betrayal, when stemming from childhood, results in an expectation that betrayals will occur again and again, so a person is constantly anticipating them.
Synonyms
disloyalty, treachery, bad faith, faithlessness, falseness, duplicity, deception, double-dealing;
breach of faith, breach of trust, stab in the back;
literary perfidy

betrayer

noun
More example sentences
  • Therefore, women who do not identify as lesbians, especially women who sometimes have relationships with other women, are branded as traitors, turncoats and betrayers of the greater sisterhood.
  • So now, as Robin points out, us anti-war, would-be dissenters, deserters and betrayers are to be offered a wide-ranging smorgasbord of humanitarian pledges to get us back on the New Labour bus.
  • But once the Turks go in, you can rely on a large movement of the New-Old Iraqi Army up there to fight the Nato-linked, EU-corrupted apostate betrayers of the capital of the Caliphs.
Synonyms
renegade, quisling, double agent, collaborator, informer, mole, stool pigeon;
informal snake in the grass, stoolie, rat, scab, fink

Definition of betray in: