Translation guide
A sexual liaison is a secret or brief sexual relationship, often outside of a committed partnership. In Japanese, the expression depends on the nature of the relationship—whether it is an affair, a one-night encounter, or a casual fling.
A sexual relationship outside of marriage or a committed partnership, often kept secret.
The most common term for an extramarital affair. It implies a sexual relationship and carries a strong negative connotation. Used in both spoken and written Japanese.
彼は不倫をしている。
He is having an affair.
不倫関係がバレた。
The affair was exposed.
Refers to cheating or infidelity, but can be broader than 不倫, sometimes including emotional affairs or one-time flings. Often used in casual conversation.
彼氏が浮気した。
My boyfriend cheated on me.
Literally 'secret meeting,' often used for clandestine romantic or sexual encounters. More literary or formal than 不倫.
二人は密会を重ねた。
The two had repeated secret meetings.
A short-term sexual relationship, often a single encounter without ongoing commitment.
Literally 'one-night-only relationship,' this is the standard phrase for a one-night stand. Neutral and widely understood.
それは一夜限りの関係だった。
It was a one-night stand.
Slang abbreviation of 'sex friend,' meaning a friend with benefits. Implies an ongoing casual sexual relationship, not necessarily a one-time event.
彼はセフレを探している。
He's looking for a friend with benefits.
Literally 'play,' used euphemistically for casual sex or a fling. Often used in the phrase 遊びの関係 (play relationship).
A non-committed, often short-term sexual relationship that may involve multiple encounters.
Literally 'physical relationship,' this is a direct and neutral term for a sexual relationship without romantic commitment. Common in both spoken and written contexts.
二人は肉体関係を持っている。
They have a sexual relationship.
Refers to a love affair or sexual liaison, often with a slightly literary or dramatic nuance. Can imply passion or secrecy.
Simply 'relationship,' but when context implies a sexual aspect, it can mean a sexual liaison. Often used with modifiers like 深い (deep) or 男女の (between man and woman).
不倫 specifically refers to an extramarital affair and is a serious accusation. 浮気 is broader, covering any cheating or infidelity, including emotional affairs or one-time flings, and is more commonly used in casual speech.
不倫は離婚の原因になる。
An affair can lead to divorce.
浮気くらい許せる？
Can you forgive a little cheating?
The English word 'liaison' can mean a communication link or intermediary, but in the sexual sense, direct translations like リエゾン are not used in Japanese. Stick to the terms above depending on the context.
二人の不倫関係は数ヶ月続いた。
Their sexual liaison lasted for months.
それは一夜限りの関係に過ぎなかった。
It was just a brief sexual liaison.
It was just a fling.
They indulged in a love affair.
彼女と関係を持った。
I had a sexual relationship with her.