What does adulterous mean?
"Adulterous" is an adjective describing sexual unfaithfulness within a marriage or committed relationship — either the person who strays or the affair itself can be called adulterous. It derives from "adultery," the act of voluntary sexual intercourse between a married person and someone other than their spouse. The word appears most often in journalism, fiction, legal writing, and everyday discussion of infidelity: one might speak of an adulterous affair, an adulterous husband, or adulterous conduct in a divorce case. Its tone is formal to neutral but morally charged, carrying connotations of betrayal and wrongdoing rooted in centuries of religious and legal condemnation of infidelity. It is more direct and judgemental than euphemistic alternatives such as "extramarital." A related but distinct term, "adulterated," refers instead to something made impure — contaminated food or drink, for instance — a reminder of the shared Latin root from which both words descend. The word remains firmly established in modern English across British and American usage.
adjectiveRelating to or involving adultery; having sexual relations with someone other than one's spouse or partner.
- Guilty of or characterized by adultery; sexually unfaithful to a spouse.
- Relating to, involving, or suggestive of adultery.
"The novel centres on an adulterous affair that shatters two families."
"She discovered her husband's adulterous relationship through a series of text messages."
"The film portrays the adulterous couple with surprising sympathy rather than judgement."
In many countries, being adulterous wasn't just a moral failing — it was a crime, and in some places it still is.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of adulterous
"Adulterous" comes from "adultery," which entered English from Old French in the medieval period and ultimately traces back to the Latin "adulterium," meaning illicit intercourse or corruption. The Latin root "alter" means "other," so the underlying sense involves giving oneself to another. The adjective form developed later in English, alongside related words such as "adulterer" and "adulterate," all sharing this Latin ancestry.
Related word forms
How adulterous is actually used
Formal to neutral in register; common in journalism, literature, and legal contexts. It carries strong moral and often religious connotations, so it tends to sound more condemnatory than neutral terms like "extramarital."
Easily confused with adulterous
"Adulterated" describes something (usually food, drink, or a substance) made impure by adding inferior ingredients, while "adulterous" describes sexual unfaithfulness within marriage.