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
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The Grammy winner, 31, who debuted late last month as Zidler in the Tony-winning adaptation of the 2001 musical film, will now be taking her final bow on Friday — less than a week after her post Saturday accusing 36-year-old Thompson of infidelity.—
Jami Ganz,
New York Daily News,
28 Apr. 2026
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Authorities painted a picture of fights and arguments — including when Ashley accused him of infidelity — that ratcheted up to the killings.—
Meredith Colias-Pete,
Chicago Tribune,
28 Apr. 2026
Noun
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The friendship betrayal/love triangle of Ciara Miller, West Wilson, and Amanda Batula is still being dissected through thousands of TikTok and Instagram comments.—
Bethy Squires,
Vulture,
30 Apr. 2026
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The betrayal of Zambada sparked a vicious battle for control of the Sinaloa cartel that has resulted in thousands of deaths.—
Kate Linthicum,
Los Angeles Times,
30 Apr. 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
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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
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Public plans often have more restrictions based on misconduct, but the standard for forfeiture typically relies on a criminal conviction, according to experts.—
Anna Liss-Roy The Washington Post,
Arkansas Online,
27 Apr. 2026
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That swing drew a 10-minute misconduct penalty and an Avs power play to end the stanza.—
Sean Keeler,
Denver Post,
27 Apr. 2026
Noun
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Under existing law, lawmakers can lose their pensions if convicted of a federal crime that relates to public corruption, espionage, treason or several other national security offenses.—
Anna Liss-Roy The Washington Post,
Arkansas Online,
27 Apr. 2026
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He is later suspected of treason when a petition alleges that he had been declared the rightful king by his armorer.—
Gitanjali Roy,
Encyclopedia Britannica,
23 Apr. 2026
Noun
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But, Keoghan said, the masses primarily only saw the first video, which fueled the widespread cheating rumors about him.—
Rachel Raposas,
PEOPLE,
28 Apr. 2026
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But even for in-person classes, adaptations to prevent LLM cheating are often concessions that reduce pedagogical quality.—
ArsTechnica,
ArsTechnica,
13 Apr. 2026
Cite this Entry
“Unfaithfulness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfaithfulness. Accessed 4 May. 2026.
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