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
Coming to the glum realization that love isn’t outlasting infatuation is trickier to write about than a more incendiary subject like unfaithfulness, but Rodrigo pulls it off.
—
Chris Willman, Variety, 12 June 2026
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
Chris Willman, Variety, 12 June 2026
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
Recent Examples of Synonyms for unfaithfulness
Noun
-
The woman and Cooper were both arrested two weeks ago when an altercation began at Cooper's residence over allegations of infidelity.—
Armando Salguero OutKick,
FOXNews.com,
17 June 2026
-
That factored into her willingness to give her husband a second chance after his infidelity.—
Lisa Respers France,
CNN Money,
16 June 2026
Noun
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Figo famously made the ultimate betrayal in 2000 when Perez became Real Madrid president for the first time.—
Tom Sanderson,
Forbes.com,
18 June 2026
-
His jealousy provokes an act of betrayal and cruelty.—
Stephanie Zacharek,
Time,
18 June 2026
Noun
-
The filings alleged adultery as the reason behind the divorce.—
Brandi D. Addison,
USA Today,
1 June 2026
-
Public opinion is against adultery.—
Louis Menand,
New Yorker,
1 June 2026
Noun
-
Peacock’s adventures in treachery The Traitors was the top dog, scoring five prizes including Best Competition Series and Best Host for Alan Cumming.—
Erik Pedersen,
Deadline,
3 June 2026
-
Upon learning of Ava’s treachery, Deborah HOWLS.—
Jessica M. Goldstein,
Vulture,
1 May 2026
Noun
-
Alite faces multiple counts of extortion, corporate misconduct, loansharking and terroristic threats.—
ABC News,
ABC News,
22 June 2026
-
Councilman John Alite, 63, of Englishtown, was arrested on Friday and charged with multiple counts of theft by extortion, corporate misconduct, usury and terroristic threats, according to the New Jersey Attorney General's office.—
Ronn Blitzer , Tessa Hoyos,
FOXNews.com,
22 June 2026
Noun
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For example, French Marshal Henri Petain was showered with ticker tape in 1931 and later convicted of treason for heading the Vichy government that collaborated with the Nazis during World War II.—
Jennifer Peltz,
Fortune,
17 June 2026
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War complicates the domestic front, turning any dissent into treason.—
Mohammed Sergie,
semafor.com,
15 June 2026
Noun
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Other research on high school cheating found in 2020 that 64% of 70,000 high school students across the country admitted to cheating on a test, and 58% admitted to plagiarism.—
Austin Sarat,
The Conversation,
17 June 2026
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Whatever romance Rodrigo is tracing the history of apparently did not end in cheating or any other horrible behavior that would lead her back toward the kind of recriminatory rockers that were among the previous albums’ highlights.—
Chris Willman,
Variety,
12 June 2026
Cite this Entry
“Unfaithfulness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfaithfulness. Accessed 23 Jun. 2026.
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