1
as in infidelity
lack of faithfulness especially to one's husband or wife
he eventually forgave his wife's unfaithfulness
Synonyms & Similar Words
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Antonyms & Near Antonyms
2
as in betrayal
the act or fact of violating the trust or confidence of another
the jaw-dropping unfaithfulness of the person she had considered her best friend was deeply hurtful
Synonyms & Similar Words
Antonyms & Near Antonyms
3
as in adultery
a sexual encounter or relationship between a married person and someone other than their spouse
there were charges of unfaithfulness on both sides
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Antonyms & Near Antonyms
Example Sentences
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Recent Examples of unfaithfulness
According to The Daily Mail, unfaithfulness might have been the cause.
—
Lizzie Lanuza, StyleCaster, 12 Jan. 2026
Harbour also recently made headlines following the release of estranged wife Lily Allen's latest album, West End Girl, which contained references many interpreted as pointing toward alleged unfaithfulness on Harbour's part, though the actor isn't explicitly named in the lyrics.
—Joey Nolfi, Entertainment Weekly, 7 Nov. 2025
Milvia Marigliano is a hoot as Coco Vulori, an old dear friend with some very loud opinions to express, and maybe the key to helping DeSantis solve his wife’s onetime unfaithfulness.
—Pete Hammond, Deadline, 27 Aug. 2025
Lizzie Lanuza, StyleCaster, 12 Jan. 2026
Harbour also recently made headlines following the release of estranged wife Lily Allen's latest album, West End Girl, which contained references many interpreted as pointing toward alleged unfaithfulness on Harbour's part, though the actor isn't explicitly named in the lyrics.
—Joey Nolfi, Entertainment Weekly, 7 Nov. 2025
Milvia Marigliano is a hoot as Coco Vulori, an old dear friend with some very loud opinions to express, and maybe the key to helping DeSantis solve his wife’s onetime unfaithfulness.
—Pete Hammond, Deadline, 27 Aug. 2025
Recent Examples of Synonyms for unfaithfulness
Noun
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Burden’s family legacy was fractured by infidelity and a laissez faire attitude, at least in the public sphere, toward men behaving badly.—
Marc Weingarten,
Los Angeles Times,
31 Mar. 2026
-
During the documentary, the former couple also discussed Odom's infidelity.—
Ariana Quihuiz,
PEOPLE,
31 Mar. 2026
Noun
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While some conservatives have described the war as a betrayal, many other Republicans have cheered on the president’s actions.—
Michelle L. Price,
Los Angeles Times,
1 Apr. 2026
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The result is a second victimization — spiritual betrayal by those called to protect.—
Ed Gaskin,
Boston Herald,
29 Mar. 2026
Noun
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The Bible teaches that lying, stealing, adultery and coveting your neighbor’s property are sins.—
Sun Sentinel Editorial Board,
Sun Sentinel,
16 Mar. 2026
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The facile novelty of adultery is its own mask, a sexy way of dressing up a deep, frightened longing for security.—
Sara Holdren,
Vulture,
6 Mar. 2026
Noun
-
Undocumented immigrants venture from Mexico, often underestimating of the treachery of the landscape.—
Shi En Kim,
AZCentral.com,
26 Mar. 2026
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Jonathan Cute kept probing the murky realms between tourism and treachery.—
Adam Ciralsky,
Vanity Fair,
19 Mar. 2026
Noun
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Ortega said she was motivated to introduce AB 2321 because of what the auditor reported about Cal-OSHA’s Bureau of Investigation, the unit responsible for investigating death and career-ending injuries for criminal misconduct.—
Joe Rubin,
Sacbee.com,
6 Apr. 2026
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The news that someone was seen with him has, of course, been received with a lot of interest, particularly considering that since his arrest for suspicion of misconduct in public office, neither his ex, Sarah Ferguson, nor his daughters, Princess Eugenie and Princess Beatrice, have visited him.—
Lizzie Lanuza,
StyleCaster,
6 Apr. 2026
Noun
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Consider this evilmeister’s brazen acts of treason and revenge, unbounded deceit, swinish immorality and negative role modeling.—
Voice of the People,
New York Daily News,
5 Apr. 2026
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She was imprisoned in Salimgarh Fort (a part of Red Fort) in Delhi by her father for more than 20 years for inciting her brother, Muhammad Akbar, to commit treason.—
Tamanna Nangia,
Encyclopedia Britannica,
2 Apr. 2026
Noun
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There seems to be a widespread perception that musicians who use artificial intelligence are engaged in a form of cheating.—
Kelefa Sanneh,
New Yorker,
30 Mar. 2026
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There is no rampant cheating or election fraud in California.—
Mark Z. Barabak,
Mercury News,
26 Mar. 2026
Cite this Entry
“Unfaithfulness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfaithfulness. Accessed 8 Apr. 2026.
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