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.
Samantha Perkins, 36, a TikTok creator who posts about her own experience with financial infidelity, said she found “Strangers” relatable “for anyone who’s been through any kind of relational betrayal.”
From The Wall Street Journal • Apr. 17, 2026
Burden’s family legacy was fractured by infidelity and a laissez faire attitude, at least in the public sphere, toward men behaving badly.
From Los Angeles Times • Mar. 31, 2026
In “Anna Karenina,” for instance, Tolstoy immediately plunges into a melodrama of infidelity, marriage proposals and ballroom dancing.
From The Wall Street Journal • Mar. 11, 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
Woodhull’s article criticized Beecher’s hypocrisy, not his infidelity.
From "Votes for Women!" by Winifred Conkling
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.
