Synonyms of unsound

unsound

adjective

ˌən-ˈsau̇nd 

1

as in sick

temporarily suffering from a disorder of the body

an unsound horse that will have to be disqualified from the race

Synonyms & Similar Words

• sick
• poorly
• bad
• ill
• unhealthy
• shaky
• weak
• down
• unwell
• dizzy
• ailing
• out of sorts
• indisposed
• under the weather
• peaky
• sickened
• troubled
• peaked
• fragile
• punk
• run-down
• symptomatic
• feeble
• diseased
• lousy
• invalid
• disabled
• disordered
• sickish
• nauseous
• weakly
• cruddy
• seedy
• queasy
• frail
• infirm
• seasick
• sickly
• woozy
• decrepit
• squeamish
• debilitated
• feverish
• airsick
• nauseated
• achy
• afflicted
• qualmish
• incapacitated
• hypochondriacal
• carsick
• light-headed
• hypochondriac

Antonyms & Near Antonyms

• sound
• whole
• well
• healthy
• wholesome
• healthful
• conditioned
• hale
• better
• fit
• cured
• able-bodied
• strong
• improved
• recovering
• robust
• tough
• well-conditioned
• mending
• hardy
• lusty
• hearty
• rugged
• stalwart
• flourishing
• bouncing
• rehabilitated
• thriving
• flush
• chipper
• blooming
• recuperating
• convalescing

2

as in unreasonable

not using or following good reasoning

it is clearly unsound to argue that just because a scientific explanation for that phenomenon does not currently exist, no such explanation is possible

Synonyms & Similar Words

• unreasonable
• irrational
• unreasoning
• illegitimate
• misleading
• weak
• illogical
• unreasoned
• absurd
• foolish
• fallacious
• invalid
• silly
• nonrational
• inconsequent
• meaningless
• inconsequential
• weird
• inconsistent
• specious
• unusual
• strange
• misguided
• odd
• sophistic
• nonsensical
• asinine
• insane
• unconsidered
• random
• preposterous
• disordered
• ill-advised
• disorganized
• surreal
• unconvincing
• eristic
• half-baked
• unaccountable
• wacky
• inexplicable
• mad
• nutty
• unexplainable
• senseless
• reasonless
• peculiar
• rambling
• Kafkaesque

Antonyms & Near Antonyms

• logical
• sound
• rational
• reasonable
• valid
• wise
• sensible
• sane
• justified
• sober
• well-founded
• reasoned
• well-grounded
• informed
• enlightened
• plausible
• solid
• clear
• just
• persuasive
• credible
• compelling
• commonsense
• certain
• organized
• cogent
• convincing
• true
• sure
• satisfying
• ordered
• demonstrated
• confirmed
• established
• substantiated
• validated
• corroborated

3

as in insane

unable to think in a clear or sensible way

disgruntled relatives tried to prove that the woman was of unsound mind when she made her will

Synonyms & Similar Words

• insane
• psychotic
• mad
• maniacal
• mental
• crazy
• unbalanced
• disturbed
• foolish
• nuts
• demented
• irrational
• unhinged
• deranged
• strange
• psycho
• crazed
• around the bend
• cracked
• loco
• daft
• eccentric
• nutty
• certifiable
• out to lunch
• depressed
• brainsick
• non compos mentis
• haywire
• batty
• off
• queer
• unreasonable
• bonkers
• disordered
• fey
• ballistic
• obsessed
• delusionary
• off one's rocker
• bats
• aberrant
• distraught
• distracted
• delusional
• loopy
• off one's gourd
• nuclear
• odd
• out of one's head
• off one's head
• crackers
• frantic
• hysterical
• delirious
• wud
• dotty
• oddball
• witless
• senseless
• touched
• pixilated
• potty
• ape
• berserk
• monomaniacal
• frenzied
• teched
• monomaniac
• fixated
• raving
• wigged-out
• bananas
• amok

Antonyms & Near Antonyms

• sound
• rational
• reasonable
• balanced
• sane
• clear
• wise
• lucid
• sensible
• judicious
• normal
• healthy
• compos mentis
• uncrazy
• well-adjusted
• unneurotic

4

as in erroneous

not being in agreement with what is true

an unsound and pernicious stereotype

Synonyms & Similar Words

• erroneous
• inaccurate
• incorrect
• wrong
• false
• untrue
• misleading
• invalid
• inexact
• untruthful
• distorted
• off base
• specious
• deceptive
• off
• fraudulent
• fallacious
• counterfactual
• delusive
• illusory
• spurious
• unproven
• fictitious
• deceitful
• dishonest
• mendacious
• untested
• awry
• delusory
• lying
• invented
• amiss
• askew
• unconfirmed
• fabricated
• made-up
• trumped-up

Antonyms & Near Antonyms

• correct
• sound
• valid
• proper
• true
• right
• accurate
• factual
• precise
• exact
• demonstrated
• confirmed
• established
• errorless
• tested
• veracious
• perfect
• proven
• impeccable
• faultless
• flawless
• letter-perfect

Example Sentences

Recent Examples of unsound

Denials based on unwritten or misapplied rules or standards, or perhaps on subjective personal preferences, would be on unsound standing. — Nicole R. Kurtz, Miami Herald, 7 May 2026

What becomes alarmingly evident through the key assumptions check is how many of the current responses expect a quick resolution of the conflict — a supposition that is unsound, or at least unsupported. — Judd Devermont, semafor.com, 27 Apr. 2026

The logic behind Liam Rosenior’s shift to a back five at Brighton & Hove Albion on Tuesday was not entirely unsound. — Conor O'Neill, New York Times, 22 Apr. 2026

What is deeply concerning is that the District Attorney is choosing to proceed on a case that is fundamentally unsound and cannot be proven at trial. — ABC News, 2 Apr. 2026