UNFOUNDED Synonyms: 92 Similar and Opposite Words

unfounded

adjective

ˌən-ˈfau̇n-dəd

Definition of unfounded

as in unreasonable

having no basis in reason or fact the accusation proved to be unfounded

Synonyms & Similar Words

Relevance

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 unfounded Supporters of the rule change also spoke against the COVID vaccine and the measles, mumps and rubella vaccine (MMR), repeating unfounded claims, such as that doctors make money from vaccines and that vaccines cause autism. — Ana Goñi-Lessan, Sun Sentinel, 8 Oct. 2026 In the lead-up to the 2022 vote, Jair Bolsonaro repeatedly cast unfounded doubts on Brazil's electronic voting system. — Arkansas Online, 4 Oct. 2026 Alito’s concerns are not unfounded, as threats to members in recent history have raised alarm about justices’ safety. — Claire Carter, The Washington Examiner, 4 Oct. 2026 In the lead-up to the 2022 vote, Jair Bolsonaro repeatedly cast unfounded doubts on Brazil’s electronic voting system. — Eléonore Hughes, Los Angeles Times, 3 Oct. 2026 See All Example Sentences for unfounded

Recent Examples of Synonyms for unfounded

Adjective

But Michael Edney, who worked at the OLC under Bush, said the opinion’s reading of executive privilege was not unreasonable, given the importance that some presidents place on outside consultation.

— Perry Stein, Washington Post, 18 Oct. 2026
Both sides have accused each other of being unreasonable and of ignoring practical concerns about voting and election security, though in very different ways.

— Kevin Rector, Los Angeles Times, 17 Oct. 2026

Definition of unreasonable

Adjective

Trump’s obsession with baseless election fraud claims and threats to rig or militarize our elections won’t help the recent college grad who’s sent out 300 resumes but can’t get a job.

— S.E. Cupp, New York Daily News, 8 Oct. 2026
Homeland Security Secretary Markwayne Mullin publicly claimed in July — without providing evidence — that there may be more than 190,000 such voters on California rolls, a claim California officials dismissed as baseless.

— Kevin Rector, Los Angeles Times, 29 Sep. 2026

Definition of baseless

Adjective

Ye Khaung Kyaw and the two other men charged in connection with the case have said the accusations against them are groundless.

— Arkansas Online, Arkansas Online, 24 Sep. 2026
Social media in South Korea have been filled with messages stoking fears about safety on Jeju, with some spreading groundless rumors and deriding the island.

— Hyung-Jin Kim, Los Angeles Times, 27 Aug. 2026

Definition of groundless

Adjective

Internal affairs complaints The lawsuit identifies five internal complaints filed against Sumstad between December 2022 and October 2025 and alleges each was dismissed, deemed unsubstantiated or ended in her exoneration.

— Ben Wheeler, Kansas City Star, 24 Sep. 2026
Somehow this unsubstantiated story became internationally known with almost no major media explicitly reporting it, and before the modern version of the internet.

— Allen Salkin, HollywoodReporter, 14 Sep. 2026

Definition of unsubstantiated

Adjective

While we are relieved that Heidi has received medical care and is safe, we are outraged by this unwarranted attack on a journalist doing her job and urge a thorough investigation and follow-through from authorities.

— Arkansas Online, Arkansas Online, 17 Oct. 2026
Critics have argued that much of the data collected is from people who are not suspected of any wrongdoing, amounting to unwarranted surveillance of lawful activities.

— Carlos E. Castañeda, CBS News, 29 Sep. 2026

Definition of unwarranted

Browse Nearby Words

unfortunately

unfounded

unfree

See all Nearby Words

Cite this Entry

Style

“Unfounded.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unfounded. Accessed 21 Oct. 2026.

Copy Citation

Synonyms of unfounded

adjective

Example Sentences

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Word of the Day

jilt

Popular in Grammar & Usage

Merriam-Webster’s Great Big List of Words You Love to Hate

'Can' vs. 'May'

'Affect' vs. 'Effect'

More Commonly Mispronounced Words

Is it 'nerve-racking' or 'nerve-wracking'?

Popular in Wordplay

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Did 'orange' the fruit or the color come first?

Even More Bird Names that Sound Like Insults (and Sometimes Are)

12 Lovely and Unusual Words for the Natural World

Popular

Merriam-Webster’s Great Big List of Words You Love to Hate

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Games & Quizzes