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
Synonyms & Similar Words
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
-
The attorney general has faced allegations of infidelity.—
Fort Worth Star-Telegram,
Fort Worth Star-Telegram,
27 May 2026
-
Paxton has managed to hang on to a lead in polling, despite having been persistently embroiled in scandals involving allegations of infidelity, fraud and abuse of office.—
Washington Post staff,
Washington Post,
26 May 2026
Noun
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But somewhere along the way, a portion of the WNBA ecosystem — fans, players and even some media members — started treating criticism as betrayal.—
Amber Harding OutKick,
FOXNews.com,
14 May 2026
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The sequel series is based on similar – and familiar – concepts of love, loyalty and betrayal, once again set in the mafia underworld.—
Jesse Whittock,
Deadline,
14 May 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
-
Upon learning of Ava’s treachery, Deborah HOWLS.—
Jessica M. Goldstein,
Vulture,
1 May 2026
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Inflamed by Ratansen’s adviser’s account of Padmavati’s beauty, Alauddin Khalji storms the fortress by treachery rather than valor.—
Encyclopedia Britannica,
Encyclopedia Britannica,
9 Apr. 2026
Noun
-
Hydee Feldstein Soto’s first term was marked by an explosion in costly litigation against the city and allegations of misconduct and mistreatment of employees.—
Sonja Sharp,
Los Angeles Times,
23 May 2026
-
Labor Secretary Lori Chavez-DeRemer resigned in April after being the target of various misconduct investigations.—
Arkansas Online,
Arkansas Online,
23 May 2026
Noun
-
Over the past year, a group of lawyers recorded 486 state treason and espionage cases brought against Russian scientists, bureaucrats, military figures, and other government employees.—
Anna Nemtsova,
Time,
23 May 2026
-
Deliberation continued for months before Burr was acquitted, in a strict reading of the definition of treason that still echoes today.—
Encyclopedia Britannica,
Encyclopedia Britannica,
19 May 2026
Noun
-
Widespread cheating must be stopped.—
Ann Kirschner,
Forbes.com,
22 May 2026
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Since there have been classrooms, there’s been student cheating.—
Fiction Non Fiction,
Literary Hub,
21 May 2026
Cite this Entry
“Unfaithfulness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfaithfulness. Accessed 28 May. 2026.
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