性 行 為(せいこうい)

せいこうい

noun

sexual intercourse; sexual activity

action health

1. sexual intercourse; sexual activity; sexual act

Physical sexual activity between individuals. A neutral, formal term used in medical, legal, and educational contexts.

性行為(せいこうい)による感染(かんせん)リスクがある。

There is a risk of infection through sexual activity.

学校(がっこう)で性行為(せいこうい)に関(かん)する教育(きょういく)が行(おこな)われている。

Education about sexual activity is provided at schools.

同意(どうい)のない性行為(せいこうい)は犯罪(はんざい)である。

Sexual activity without consent is a crime.

A compound of 性(せい) (sex; gender) and 行為(こうい) (act; conduct). This is the standard formal, neutral term for sexual activity in Japanese, used in medical documents, legal texts, health education, and news reporting. It carries no vulgar or casual connotation.

Common collocations

性行為(せいこうい)感染症(かんせんしょう): sexually transmitted infection
同意(どうい)のある性行為(せいこうい): consensual sexual activity
性行為(せいこうい)に及(およ)ぶ: to engage in sexual activity (formal)
安全(あんぜん)な性行為(せいこうい): safe sex

Similar words

セックス: sex — direct loanword, less formal
性交(せいこう): sexual intercourse — clinical/medical term, narrower in scope
営(いとな)み: intimate relations (euphemistic) — a literary, indirect way to refer to sexual activity

Related Words

Compare: 営(いとな)み (intimate relations)

Related: 性的(せいてき) (sexual)

general

Added 2026.4.29 22:44 · Revised 2026.9.2 13:02

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