infidelity
Americannoun
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marital disloyalty; adultery.
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unfaithfulness; disloyalty.
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lack of religious faith, especially Christian faith.
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a breach of trust or a disloyal act; transgression.
noun
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lack of faith or constancy, esp sexual faithfulness
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lack of religious faith; disbelief
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an act or instance of disloyalty
Other Word Forms
Noun Inflected Forms
Etymology
Origin of infidelity
First recorded in 1375–1425; late Middle English, from Latin infidēlitās; equivalent to infidel + -ity
Explanation
Someone guilty of infidelity is cheating on a spouse or romantic partner. A common cause of divorce and heartbreak is infidelity. Fidel means "faithful" or "loyal." Tack on the prefix in, which means "not," and you've got yourself infidelity — the act of being unfaithful. The word can also be used to refer to someone's religious beliefs. Run angrily through a church and claim that God doesn't exist, and your fellow churchgoers will think you lack faith, or that you are guilty of infidelity.
Vocabulary lists containing infidelity
George Washington's Farewell Address (1796)
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The Woman Warrior
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What to the Slave is the Fourth of July?
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
His co-writer, Hilary Beard, said that he insisted in detailing his infidelity in the book as a cautionary tale to demonstrate what his behavior did to his family and his business.
From The Wall Street Journal ● Jul. 9, 2026
Dawn Rhodes's death followed the end of the couple's relationship, and they were in the process of separating after revelations of infidelity.
From BBC ● Jul. 7, 2026
His wife, state Sen. Angela Paxton, is divorcing him on “biblical grounds,” accusing him of infidelity.
From Salon ● Jun. 17, 2026
He claimed the child wasn’t his but the product of his ex-wife’s infidelity.
From Los Angeles Times ● May 22, 2026
Up until the time of Harriet’s discovery of John Tubman’s infidelity, she had been guiding escaping slaves to the North and freedom largely because she wanted to rescue members of her own family.
From "Harriet Tubman: Conductor on the Underground Railroad" by Ann Petry
In middle age, Delery Anhalt has moved back to her hometown of New Orleans from Washington, D.C., after learning about her husband’s infidelities.
From The Wall Street Journal ● Apr. 23, 2026
The NBA champion is on an apology tour with the Kardashian family in which he addresses and attempts to make amends for his past infidelities and the familial fallout that came from them.
From Los Angeles Times ● Nov. 20, 2023
Decades of shortcuts, cheap-outs, infidelities and distortions gave red-sauce cuisine a reputation as a debased, degraded creature.
From New York Times ● Oct. 26, 2021
Jagger's infidelities, which finally convinced Hall to leave him in 1999, began during their courtship.
From Salon ● Jul. 2, 2021
His laughing with Kainene, telling Kainene about Aunt Elizabeth, watching Kainene smoke, surely had to be infidelities; they felt so.
From "Half of a Yellow Sun" by Chimamanda Ngozi Adichie
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
