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

This not only makes the shade problem worse, Chamberlain says, but makes the tree more structurally unsound and vulnerable to damage in harsh weather conditions. — Peg Aloi, The Spruce, 30 Mar. 2026