Translation guide
The English verb "betray" covers a range of meanings from personal disloyalty to revealing secrets or showing unintended emotions. This guide organizes the most common and useful Japanese expressions by these distinct meanings, helping learners choose the right word for the context.
To be disloyal or unfaithful to someone who trusts you, such as a friend, partner, or organization.
The most common and direct translation for personal betrayal. It can be used for friends, lovers, allies, or one's own principles.
彼は親友を裏切った。
He betrayed his best friend.
彼女は私の信頼を裏切った。
She betrayed my trust.
Literally 'to flip sides while sleeping', meaning to switch allegiance, often in a dramatic or opportunistic way. Common in historical or political contexts.
将軍は敵側に寝返った。
The general betrayed his side and went over to the enemy.
To go against or defy someone's expectations, orders, or trust. Often used for betraying a promise or principle.
彼は約束に背いた。
He betrayed his promise.
To disclose secret information, often to an enemy or unauthorized person.
A straightforward phrase meaning 'to leak a secret'. It implies a breach of confidence.
彼は会社の秘密を漏らした。
He betrayed company secrets.
To inform on someone, often to authorities. Carries a nuance of betrayal through reporting.
彼は仲間を警察に密告した。
He betrayed his comrades to the police.
Can also be used for betraying by revealing secrets, especially in dramatic contexts.
To show one's true feelings or thoughts without meaning to, often through facial expression or action.
Literally 'one's true feelings come out'. Used when someone accidentally reveals what they really think.
彼の表情に本音が出ていた。
His expression betrayed his true feelings.
To show on one's face. Often used when emotions are visible despite efforts to hide them.
驚きが顔に出てしまった。
My surprise betrayed itself on my face.
When one's voice trembles, betraying nervousness or emotion. More specific physical betrayal.
彼の声が震えて、緊張を裏切っていた。
His voice trembled, betraying his nervousness.
To cheat on a partner or be sexually unfaithful.
The most common term for cheating in a romantic relationship. It implies a breach of trust.
彼は彼女を裏切って浮気した。
He betrayed her by cheating.
Specifically refers to extramarital affairs. More formal and serious than 浮気.
彼は妻を裏切って不倫した。
He betrayed his wife by having an affair.
When describing how a facial expression or action unintentionally reveals feelings, using 裏切る directly can sound unnatural. Instead, use phrases like 本音が出る or 顔に出る.
裏切る is the general term for betrayal of trust. 背く emphasizes going against rules, expectations, or orders, and is often used for abstract things like promises or principles.
The spy betrayed his country and handed over information.