Meaning : Reveal unintentionally.
Her smile betrayed her true feelings.
Synonyms : bewray
Meaning : Deliver to an enemy by treachery.
Judas sold Jesus.
The spy betrayed his country.
Synonyms : sell
Meaning : Disappoint, prove undependable to. Abandon, forsake.
His sense of smell failed him this time.
His strength finally failed him.
His children failed him in the crisis.
Synonyms : fail