If you have seen the word adultery in a book, news story, legal document, or conversation about marriage, you may wonder exactly what it means. The simplest adultery meaning involves a married person having sexual relations with someone who is not their spouse. However, people sometimes use the word more broadly in everyday conversation than in its traditional dictionary or legal definition.
Quick answer: Adultery means voluntary sexual intercourse involving a married person and someone other than that person’s spouse. In everyday conversation, people may use the term more broadly for an extramarital affair, but words such as infidelity and cheating can cover a wider range of romantic, emotional, or sexual behavior.
What Does Adultery Meaning?
Adultery is the act of a married person having voluntary sexual intercourse with someone other than their spouse. Merriam-Webster gives this definition essentially, and Cornell Law School’s Legal Information Institute similarly describes adultery as a form of extramarital sexual intercourse involving a married person. The traditional meaning therefore centers on both marriage and sexual activity.
At least one person involved must be married for the conventional definition to apply. If two unmarried people are romantically or sexually involved with each other, their relationship would not normally be called adultery. If a married person becomes sexually involved with an unmarried person, however, the married person’s conduct can be described as adultery.
The word often carries a negative or serious tone because it refers to breaking the expectation of sexual faithfulness within a marriage. You are more likely to encounter it in formal discussions, religious contexts, news reports, literature, or conversations about divorce than in casual speech. In everyday American English, people frequently use words such as cheating, having an affair, or infidelity instead.
Adultery Pronunciation and Word Forms
In American English, adultery is commonly pronounced approximately as uh-DUHL-tuh-ree, with the main stress on the second syllable. The word is a noun, so it names the act or behavior rather than describing a person. Several related words come from the same word family and are useful when reading or writing about the subject.
| Word | Part of speech | Simple meaning |
|---|---|---|
| Adultery | Noun | Sexual unfaithfulness involving a married person |
| Adulterous | Adjective | Relating to or involving adultery |
| Adulterer | Noun | A person who commits adultery |
| Infidelity | Noun | Unfaithfulness in a romantic relationship or marriage |
| Extramarital | Adjective | Existing or occurring outside a marriage |
For example, someone might refer to an adulterous relationship when describing an affair involving a married person. A writer could also say that a character committed adultery, which is one of the most common ways the noun appears in a sentence. Understanding these forms makes it easier to recognize the meaning even when the exact word adultery is not used.
Adultery vs. Infidelity vs. Cheating
Adultery, infidelity, and cheating are related terms, but they are not always interchangeable. Adultery has the narrowest traditional meaning because it normally involves a married person and sexual intercourse outside the marriage. Infidelity is broader and can describe a romantic or sexual relationship outside a marriage or committed partnership.
Cheating is the most informal of the three terms and depends heavily on a particular relationship’s boundaries. A couple may consider secret kissing, romantic messaging, dating-app use, or an emotional relationship to be cheating even when no sexual intercourse occurred. Those behaviors may therefore qualify as infidelity or cheating without necessarily meeting the traditional definition of adultery.
| Term | Marriage required? | Usually sexual? | Can include emotional behavior? |
|---|---|---|---|
| Adultery | Traditionally, yes | Yes | Usually not by itself |
| Infidelity | Not always | Often, but not necessarily | Yes |
| Cheating | No | Not necessarily | Yes |
| Affair | No fixed requirement | Often romantic or sexual | Often |
This distinction matters when interpreting someone’s words. A person who says, “My partner cheated,” may be referring to behavior ranging from secret romantic messages to a sexual relationship. A statement specifically alleging adultery usually carries a more particular meaning, especially when it appears in a legal context.
Examples of Adultery in a Sentence
Seeing a word in context can make its meaning easier to remember. Adultery is usually used as a noun after words such as commit, accuse, admit, discover, or grounds for. The following original examples show several natural ways to use it in American English.
- The couple separated after she discovered her husband’s adultery.
- He denied the allegation that he had committed adultery during the marriage.
- Adultery became an important issue during their divorce proceedings.
- The novel explores betrayal, adultery, forgiveness, and a marriage’s breakdown.
- She considered adultery a serious violation of their marriage vows.
- State law may determine whether adultery matters in a particular divorce case.
Notice that people normally say “commit adultery” rather than “do adultery” in ordinary English. Other common expressions include “accused of adultery” and “admitted to adultery” in news reports. Legal writing often adds a time frame, as in “adultery during the marriage” in a divorce petition. Learning these combinations can help English learners use the term more naturally.
Does Adultery Always Involve Sex?
Under the traditional dictionary definition, adultery refers specifically to sexual intercourse outside marriage. That means an emotional relationship, secret texting, flirting, or kissing does not automatically fit the narrow definition, even if a spouse considers the behavior a betrayal. Merriam-Webster’s definition specifically describes voluntary sexual intercourse involving a married person and someone other than that person’s spouse.
Everyday relationship language is less precise, however, and people sometimes use adultery loosely to describe an extramarital affair in general. Couples may also establish their own boundaries about what counts as unfaithfulness, so behavior that is not technically adultery can still seriously violate a relationship’s expectations. If precision matters, especially in legal writing, it is better to distinguish between adultery, infidelity, emotional affairs, and other forms of cheating.
Is Adultery the Same as Having an Affair?
Not necessarily, because “affair” is broader and less precise. An affair generally describes a secret romantic or sexual relationship outside an existing committed relationship, and everyday usage does not always require marriage. Adultery, by contrast, traditionally requires that at least one person involved be married and generally refers to sexual conduct.
An affair involving a married person may therefore also be described as adulterous. However, a romantic relationship involving two unmarried people who are each violating other relationship commitments might be called cheating or an affair without being adultery in the traditional sense. The correct term depends on marital status, the behavior involved, and the context in which the word is being used.
Is Adultery Illegal in the United States?
No single answer applies uniformly across the United States because marriage and divorce laws differ by state. Some states permit adultery to be raised as a fault-based ground for divorce, while others rely entirely or primarily on no-fault divorce rules. Cornell Law School notes that adultery can be relevant in fault divorce and that some states may also consider marital fault when addressing issues such as property or alimony.
Some states also retain old criminal statutes concerning adultery, although prosecutions under such laws are uncommon and the legal landscape has changed as states repeal older statutes. The practical consequences of an affair are therefore much more likely to arise during family-law proceedings than through a criminal prosecution. Adultery also remains an offense under U.S. military law. A 2019 revision of the Manual for Courts-Martial renamed it extramarital sexual conduct under Article 134 of the Uniform Code of Military Justice, published as 10 U.S. Code section 934 by Cornell Law School’s Legal Information Institute. Anyone dealing with an actual divorce or legal dispute should check the current law of the relevant state rather than relying on a general definition, and it helps to know what to consider before filing for divorce.
The role of adultery in divorce can also vary significantly from one state to another. For example, the American Bar Association’s state-by-state family-law resource shows that states differ in whether they permit fault grounds and whether marital misconduct can be considered when determining alimony. Readers researching related subjects can also browse more plain-English guides to U.S. law for additional general information.
Common Misunderstandings About the Meaning of Adultery
Because adultery, cheating, affairs, and infidelity are often discussed together, several misconceptions are common. The easiest way to avoid confusion is to remember that adultery traditionally has a narrower definition than everyday words such as cheating. Marriage status and the type of conduct involved are key to that distinction.
| Common assumption | More accurate explanation |
|---|---|
| Any cheating is adultery | Cheating is broader; not every form of cheating meets the traditional definition of adultery. |
| Both people must be married | No. Traditionally, at least one participant being married is enough for adultery to be involved. |
| Emotional cheating is automatically adultery | Not under the narrow dictionary definition, although it may be considered infidelity. |
| Adultery and infidelity always mean exactly the same thing | They overlap, but infidelity can describe a wider range of behavior. |
| Adultery has the same legal effect everywhere in the U.S. | No. Its legal relevance depends on state law and individual circumstances. |
These differences are especially useful when reading legal or formal writing. In ordinary conversation, speakers may not use the terms with dictionary-level precision, so context can change what they intend to communicate. When accuracy matters, looking at the speaker’s meaning and the surrounding circumstances is more reliable than assuming every reference to cheating describes adultery.
Why the Word Adultery Can Sound More Formal Than Cheating
The word adultery has a more formal tone than cheating because it has long been used in legal, religious, literary, and moral discussions about marriage. It identifies a particular kind of marital unfaithfulness rather than serving as a general label for every possible relationship boundary violation. Legal English often narrows an everyday word in this way, much as the term unconscionable carries a precise meaning in contract law that ordinary speech does not. For that reason, a news article or court document may use adultery where friends discussing the same situation might simply say someone cheated.
Tone matters when choosing a word in your own writing. If you are discussing someone’s relationship casually, cheating or having an affair may sound more natural, while adultery works better when the person’s marital status and the sexual nature of the conduct are important. Using the more precise word can prevent readers from misunderstanding what happened.
Frequently Asked Questions
What is the simplest meaning of adultery?
Adultery means a married person voluntarily having sexual intercourse with someone other than their spouse. It is a form of marital unfaithfulness and is often associated with an extramarital affair. The traditional definition is narrower than the general concepts of cheating or infidelity.
Does adultery require marriage?
Yes, marriage is part of the traditional meaning of adultery. At least one person involved must be married for the term to apply in its conventional sense. When no participant is married, terms such as cheating or infidelity may be more appropriate depending on the situation.
Is kissing someone else considered adultery?
Kissing alone would not normally meet the traditional dictionary definition of adultery because that definition centers on sexual intercourse. A spouse or partner may still consider kissing another person to be cheating or infidelity. Relationship boundaries can therefore be violated even when conduct does not technically qualify as adultery.
What is the difference between adultery and an affair?
An affair is a broader term for a secret romantic or sexual relationship outside an existing relationship. Adultery specifically refers to sexual unfaithfulness involving a married person. An adulterous relationship can therefore be an affair, but not every affair necessarily fits the traditional adultery definition.
Is adultery a noun or an adjective?
Adultery is a noun that names the act itself. Adulterous is the related adjective used to describe behavior, relationships, or circumstances involving adultery. For example, “adultery damaged the marriage” uses the noun, while “an adulterous affair” uses the adjective.
What are synonyms for adultery?
Common related words include infidelity, cheating, unfaithfulness, affair, and extramarital relationship. These words overlap with adultery but do not always have exactly the same definition, particularly because some can apply to unmarried couples or nonsexual behavior. Merriam-Webster lists cheating and infidelity among terms closely related to adultery.
Can adultery affect divorce in the United States?
It can in some states, but the effect depends on state law and the marriage’s circumstances. Some states still recognize fault-based divorce grounds or allow certain marital conduct to factor into financial decisions, while others operate differently. A person facing an actual divorce should therefore consult current state law or a qualified family-law professional rather than assuming a nationwide rule applies.
The Bottom Line
The adultery meaning is straightforward in its traditional sense: it refers to voluntary sexual intercourse between a married person and someone who is not their spouse. The word is more specific than cheating or infidelity, which can also describe emotional, romantic, or nonsexual violations of relationship boundaries. Remembering that distinction will help you understand the term accurately whether you encounter it in everyday English, literature, news coverage, or a U.S. legal discussion.
