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
• weak
• untenable
• inconsistent
• unsound
• nonvalid
• wrong
• implausible
• unconscionable
• misled
• unconvincing
• 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

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

Secretary Kennedy’s team seeks to make autism compensable under vaccine-injury rules, turning diagnoses into groundless lawsuits while draining resources from real causes and care. — Tom Frieden, Scientific American, 21 Nov. 2025

Earlier this week, Sulton said the new criminal case is groundless and accused prosecutors of bringing additional charges because Spencer rejected a plea deal on the first case. — Vanessa Swales, jsonline.com, 17 Oct. 2025