1
as in infidelity
lack of faithfulness especially to one's husband or wife
he eventually forgave his wife's unfaithfulness
Synonyms & Similar Words
Relevance
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
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
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
-
At one point, Gates testified that Epstein used his infidelity to his wife Melinda Gates to try to keep their relationship intact.—
Lauren Green,
The Washington Examiner,
10 June 2026
-
Betrayals and scandals like this are endemic to reality TV; the Bravoverse in particular is still living in the long shadow of 2023’s Scandoval, the tectonic collapse inside Vanderpump Rules that was also fueled by inter-group infidelity.—
Kathryn VanArendonk,
Vulture,
10 June 2026
Noun
-
In terms of the season finale, Harris was intent on treating that betrayal not as an obstacle quickly overcome, but that would set the stage for a new beginning for the characters.—
Lexy Perez,
HollywoodReporter,
11 June 2026
-
In season 3, Joe must walk the line between duty and her home life, as hidden networks, foreign operatives, and personal betrayals collide.—
Derek Lawrence,
Entertainment Weekly,
11 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
-
Newton reportedly stole a computer, and there were allegations of academic misconduct.—
Mac Engel
June 15,
Fort Worth Star-Telegram,
15 June 2026
-
Political expediency, like political misconduct, is not limited to any one party.—
Clarence Page,
Chicago Tribune,
15 June 2026
Noun
-
War complicates the domestic front, turning any dissent into treason.—
Mohammed Sergie,
semafor.com,
15 June 2026
-
On this day in 1964, eight activist leaders were sentenced to life imprisonment for treason, sabotage, and conspiracy against South Africa’s apartheid government.—
Encyclopedia Britannica,
Encyclopedia Britannica,
9 June 2026
Noun
-
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
-
Just needed his seat in Congress despite his lying and cheating, kind of like the guy sitting in the White House.—
DP Opinion,
Denver Post,
8 June 2026
Cite this Entry
“Unfaithfulness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfaithfulness. Accessed 16 Jun. 2026.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
