Synonyms of well-founded

well-founded

adjective

ˈwel-ˈfau̇n-dəd 

1

as in logical

according to the rules of logic

even a well-founded argument can lead to an erroneous conclusion if one of the premises is incorrect

Synonyms & Similar Words

• logical
• reasonable
• valid
• rational
• coherent
• good
• sensible
• analytic
• well-grounded
• sound
• consequent
• empirical
• justifiable
• cognitive
• a priori
• defensible
• sustainable
• syllogistic
• tenable
• supportable
• a posteriori
• defendable
• maintainable

Antonyms & Near Antonyms

• unreasonable
• irrational
• weak
• illogical
• illegitimate
• invalid
• unsound
• fallacious
• specious
• misleading
• incoherent
• inconsequential
• unarticulated
• sophistic
• casuistic
• unscientific
• inconsequent
• absurd
• stupid
• preposterous
• mad
• insane
• fatuous
• nonsensical
• crazy
• eristic
• simpleminded
• harebrained
• thoughtless
• loony
• nutty
• unconvincing
• daffy
• witless
• senseless
• cockeyed
• half-baked
• weak-minded
• half-witted
• uncompelling

2

as in reasonable

based on sound reasoning or information

a well-founded complaint about the business's treatment of its customers

Synonyms & Similar Words

• logical
• reasonable
• reasoned
• valid
• rational
• sensible
• justified
• good
• solid
• true
• informed
• hard
• commonsense
• plausible
• firm
• validated
• sober
• commonsensical
• credible
• levelheaded
• real
• just
• actual
• convincing
• substantiated
• commonsensible
• certain
• confirmed
• sure
• cogent
• certified
• verified
• corroborated
• colorable

Antonyms & Near Antonyms

• unfounded
• unreasonable
• irrational
• groundless
• unjustified
• illogical
• invalid
• unsound
• uninformed
• unwarranted
• nonsensical
• unsubstantiated
• nonrational
• unsupported
• unreasoned
• weak
• implausible
• unconvincing
• flimsy
• false
• nonvalid
• misguided
• fallacious
• misled

Example Sentences

Recent Examples of well-founded

And the Republicans’ concern is well-founded. — Douglas E. Schoen, Washington Post, 1 Apr. 2026

Gen Z’s concerns are well-founded—and echo warnings from leading AI experts and mounting management evidence. — Steve Denning, Forbes.com, 14 June 2026

Add to that an affordability crisis hitting families’ checkbooks and many businesses’ eager push to utilize artificial intelligence, and workers’ sentiments appear well-founded. — Matt Helmer, Fortune, 23 May 2026

Advertisement Barring Platner bowing out in time—which seems unlikely—Democrats are hunkering down, desperately hoping there aren’t more Platner revelations left to come out before Election Day. — Philip Elliott, Time, 10 June 2026