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1. Reveal unintentionally
   "Her smile betrayed her true feelings";
   - bewray [archaic]
    
2. Deliver to an enemy by treachery
   "The spy betrayed his country";
   - sell
    
3. Disappoint, prove undependable to; abandon, forsake
   "His sense of smell betrayed him this time";
   - fail
    
4. Be sexually unfaithful to one's partner in marriage
   "She betrays her husband";
   - cheat on, cheat, cuckold, wander
    
5. Give away information about somebody
   "He betrayed his classmate who had cheated on the exam";
   - denounce, tell on, give away, rat [informal], grass, shop [informal], snitch [informal], stag, squeak [informal]
    
6. Cause someone to believe an untruth
   "The insurance company betrayed me when they told me they were covering my house";
   - deceive, lead astray

Derived forms: betraying, betrayed, betrays

Type of: break, bring out, cozen [literary], deceive, delude, disappoint, disclose, discover, disinform, divulge, expose, give away, inform, lay bare, lead on, let down, let on, let out, misinform, mislead, reveal, uncover, unwrap

Antonym: undeceive

Encyclopedia: Betray