Betray

To betray someone is to be disloyal and break their trust, often by helping their enemy or sharing their secrets. It can also mean to reveal something without meaning to, like when your voice betrays your fear.

From Old French “trair” or “trahir,” from Latin “trādere,” meaning “to hand over” or “to deliver.” The prefix “be-” in English often intensifies the action, so “betray” is like “thoroughly hand over.”