infidelity
Americannoun
plural
infidelities-
marital disloyalty; adultery.
-
unfaithfulness; disloyalty.
-
lack of religious faith, especially Christian faith.
-
a breach of trust or a disloyal act; transgression.
noun
-
lack of faith or constancy, esp sexual faithfulness
-
lack of religious faith; disbelief
-
an act or instance of disloyalty
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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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.
Financial infidelity can threaten relationships and shared livelihoods, and its stakes have only grown higher in our gambling-friendly, rich-on-paper era.
From The Wall Street Journal • Apr. 17, 2026
It turns out his mother lied to me about many things: her infidelity and numerous financial issues.
From MarketWatch • Feb. 19, 2026
Then came a different kind of cheating when medal-winning Norwegian biathlete Sturla Holm Laegreid confessed to infidelity in a TV interview.
From Los Angeles Times • Feb. 17, 2026
However, Jackson's later years would be punctuated by scandal, including revelations of marital infidelity and financial impropriety involving his son and political heir, Jesse Jackson Jr, who served as a congressman from Illinois.
From BBC • Feb. 17, 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
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.
