Translation guide
The concept of unfaithfulness in relationships, primarily romantic or sexual betrayal. Japanese expressions range from formal terms for infidelity to casual slang for cheating.
Expressing that someone is unfaithful in a romantic or sexual relationship, such as cheating on a partner.
The most common and versatile word for cheating or having an affair. Can be used as a noun or a suru-verb (浮気する). Implies a breach of trust in a romantic relationship, often but not always sexual.
Expressing unfaithfulness in a broader sense, such as disloyalty to a person, group, or principle.
浮気 (uwaki) is a broad term for cheating, including dating multiple people or a one-time fling. 不倫 (furin) specifically means adultery within a marriage. Use 不倫 when the unfaithful person is married, and 浮気 for non-marital relationships or when the marital status is unclear.
彼氏が浮気しているみたい。
I think my boyfriend is cheating on me.
I will never forgive cheating.
Refers specifically to an extramarital affair; adultery. More formal and serious than 浮気. Often used in legal or social contexts.
The affair was discovered and they got divorced.
Adultery is socially unacceptable.
Literally 'to straddle two forks,' meaning to two-time or date two people at the same time without their knowledge. Emphasizes the deception of maintaining multiple relationships.
He was seeing someone else while dating me. I was totally two-timed.
A formal, legalistic term for adultery. Rarely used in everyday conversation; mostly found in legal documents or historical contexts.
The crime of adultery was abolished.
Means insincerity or lack of faithfulness, often in a moral or ethical sense. Can apply to personal relationships, business, or duties.
I was disappointed by his unfaithful attitude.
Betrayal or treachery. Stronger than mere unfaithfulness; implies a deliberate act of disloyalty. Often used in dramatic or emotional contexts.
Betrayal by a friend is the most painful.
Literary or formal term for unfaithfulness, insincerity, or perfidy. Often used in written language or classical contexts.
Those who commit unfaithful acts should be punished.
He is cheating even though he's married. → He is committing adultery.
The English word 'unfaithfulness' can sound abstract or formal. In Japanese, it's more natural to use specific terms like 浮気 or 不倫 for romantic infidelity, or 不誠実 for general disloyalty. Direct translations like 不忠実 (fuchūjitsu) are rarely used and may sound unnatural.