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Synonyms

infidelity

American  
[in-fi-del-i-tee] / ˌɪn fɪˈdɛl ɪ ti /

noun

plural

infidelities
  1. marital disloyalty; adultery.

  2. unfaithfulness; disloyalty.

  3. lack of religious faith, especially Christian faith.

  4. a breach of trust or a disloyal act; transgression.


infidelity British  
/ ˌɪnfɪˈdɛlɪtɪ /

noun

  1. lack of faith or constancy, esp sexual faithfulness

  2. lack of religious faith; disbelief

  3. an act or instance of disloyalty

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.

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Vocabulary lists containing infidelity

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.

Infidelity, jealousy, malevolent neediness — there’s all manner of abhorrent behavior in this study of some notably unhappy relationships.

From New York Times • Feb. 1, 2023

Deadly Infidelity Awakening from a monthlong coma, a woman has lost the last five years of memories of her husband and daughter.

From Los Angeles Times • Jan. 1, 2022

“No! That is like going into my fears. It’s because I’m such a romantic. Infidelity breaks my heart. That’s why I write about it, because I’m obsessed with it.”

From The Guardian • Sep. 8, 2018

Infidelity used to be the leading cause of divorce among Muslims in Thailand's southern province of Pattani.

From BBC • Jun. 12, 2017

He and W. D. Herndon used to talk Infidelity in the Clerk's office in this city, about the years 1837-40.

From Abraham Lincoln: Was He A Christian? by Remsburg, John B.