Synonyms of unfounded

unfounded

adjective

ˌən-ˈfau̇n-dəd 

as in unreasonable

having no basis in reason or fact

the accusation proved to be unfounded

Synonyms & Similar Words

• unreasonable
• baseless
• groundless
• unsubstantiated
• unwarranted
• irrational
• unsupported
• invalid
• false
• unreasoned
• unnecessary
• absurd
• misleading
• illogical
• foundationless
• fallacious
• inconsistent
• weak
• nonvalid
• implausible
• wrong
• specious
• untenable
• misled
• unconscionable
• meaningless
• unconvincing
• unsound
• gratuitous
• stupid
• flimsy
• uncalled-for
• foolish
• nonsensical
• asinine
• silly
• nonlogical
• fatuous
• preposterous
• insane
• unwise
• ill-advised
• mad
• simpleminded
• wacky
• harebrained
• nutty
• senseless
• brainless
• crackpot
• crazy
• half-witted

Antonyms & Near Antonyms

• reasonable
• justified
• valid
• good
• hard
• reasoned
• confirmed
• just
• well-founded
• certified
• substantiated
• logical
• rational
• well-grounded
• true
• informed
• real
• validated
• actual
• wise
• sensible
• genuine
• certain
• verified
• sane
• sure
• corroborated
• sober
• clear
• plausible
• solid
• sound
• credible
• convincing
• compelling
• commonsense
• persuasive
• satisfying
• cogent

Example Sentences

Recent Examples of unfounded

French officials condemned the move as hostile and unfounded, while urging citizens in the West African nation to exercise heightened vigilance as reciprocal measures are considered. — Los Angeles Times, 27 June 2026

After being prosecuted at the age of 20, Powell, now 41, was released after a judge overturned his sentence of life plus five years on murder charges in the death of his best friend, Shah Walton – charges that prosecutors later agreed were unfounded. — Andy Rose, CNN Money, 26 June 2026

People with Down syndrome are still denied medical care based on unfounded medical bias. — Michelle Sie Whitten, STAT, 25 June 2026

For a year, thousands of detainees awaiting deportation were brought to the temporary detention center, with many complaining of inhumane conditions that the DeSantis administration said were unfounded. — Douglas Hanks, Miami Herald, 25 June 2026