How to say "adultery" in Japanese

Choosing the right word

不倫ふりんCommon
suru verb, intransitive verb, na-adjective, no-adjectiveThe everyday word for the 'affair' sense of adultery: a married person's secret romantic relationship outside marriage, viewed as a scandal. Typical context: news or gossip about a celebrity's extramarital affair.
隣となりの人ひとが若わかい女おんなの人ひとと不倫ふりんしているらしいよ。↗
Did you hear that our neighbor was fooling around with a younger woman?
姦通かんつうCommon
no-adjective, suru verb, intransitive verbA narrow term for adultery itself and nothing else, met mainly in legal or academic writing on adultery as an offense; seldom the word you want in everyday talk about an affair.
不義ふぎCommon
no-adjectiveCovers adultery as infidelity and, from the deceived spouse's side, cuckoldry. It frames the act as a breach of faith with strong moral coloring. Typical context: condemning a spouse's unfaithfulness as a betrayal.

Choose 不倫 for an extramarital love affair, 姦通 for adultery treated as a legal offense, and 不義 for infidelity condemned as a moral wrong or betrayal.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

Japanese equivalents

Say it right, write it right