Synonyms of groundless

groundless

adjective

ˈgrau̇n(d)-ləs 

as in unreasonable

having no basis in reason or fact

please stop making groundless accusations against innocent people

fears of a strike proved groundless

Synonyms & Similar Words

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

Antonyms & Near Antonyms

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

Example Sentences

Recent Examples of groundless

China says such allegations are groundless. — Chan Ho-Him, Fortune, 6 May 2026

The former proved ultimately groundless while the latter came to pass, but not until the market was glutted. — Michael Lynch, Forbes.com, 2 Mar. 2026

Lawmakers, judges and other public servants, all under groundless presidential attack. — James D. Zirin, Washington Post, 3 Feb. 2026

Similarly, the course of action that will bring recovery—reviving domestic manufacturing, revitalizing small towns, ensuring fairness for farmers and working people—is not an impossibility that will poison our minds with groundless optimism. — Rosa Lyster, Harpers Magazine, 30 Dec. 2025