to hurt someone who trusts you by being disloyal to them, especially by helping their enemies or sharing harmful information
Judas betrayed Jesus for thirty silver coins.
The spy betrayed his country by selling secrets to a foreign agent.
✦ Middle English betraien, from be- + Old French traïr “to betray,” from Latin tradere “to hand over.”
to reveal something hidden, such as a feeling or secret, often without intending to
Her trembling voice betrayed her fear during the interview.
A sudden blush betrayed her embarrassment.
to deceive or mislead someone so they make a mistake
Appearances can betray even the wisest traveler.
The calm sea betrayed the storm that lurked beneath.
