un·​sound | \ ˌən-ˈsau̇nd How to pronounce unsound (audio) \

Definition of unsound

: not sound: such as
a : not healthy or whole an unsound horse
b : not mentally normal : not wholly sane of unsound mind
c : not firmly made, placed, or fixed structurally unsound
d : not valid or true : invalid, specious unsound beliefs

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Other Words from unsound

unsoundly \ ˌən-​ˈsau̇n(d)-​lē How to pronounce unsoundly (audio) \ adverb

Synonyms & Antonyms for unsound


balmy, barmy [chiefly British], bats, batty, bedlam, bonkers, brainsick, bughouse [slang], certifiable, crackbrained, cracked, crackers, crackpot, cranky [dialect], crazed, crazy, cuckoo, daffy, daft, demented, deranged, fruity [slang], gaga, haywire, insane, kooky (also kookie), loco [slang], loony (also looney), loony tunes (or looney tunes), lunatic, mad, maniacal (also maniac), mental, meshuga (or meshugge), moonstruck, non compos mentis, nuts, nutty, psycho, psychotic, scatty [chiefly British], screwy, unbalanced, unhinged, wacko (also whacko), wacky (also whacky), wud [chiefly Scottish]


balanced, compos mentis, sane, sound, uncrazy

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Examples of unsound in a Sentence

The roof is structurally unsound. disgruntled relatives tried to prove that the woman was of unsound mind when she made her will

Recent Examples on the Web

In 1989, the group reviewed the Star Wars antimissile program called Brilliant Pebbles, judging it technologically unsound; the program was canceled in 1993. Ann Finkbeiner, Science | AAAS, "Jason—a secretive group of Cold War science advisers—is fighting to survive in the 21st century," 27 June 2019 An uneven foundation, outdated galvanized pipes, structurally unsound framing and overzealous tree roots meant that a more complete overhaul was called for. Hannah Morrill, ELLE Decor, "Inside Sophia Bush’s Incredible Renovation of a Classic 1950s Bungalow in Los Angeles," 24 June 2019 Currently, no such system exists, which allows importers to bring in low-quality recyclables that can only be processed using unsafe and environmentally unsound means. Adam Minter, Twin Cities, "Adam Minter: Southeast Asia should want the world’s junk," 12 June 2019 Some could also be razed when structures are found to be unsound. Esther Fung, WSJ, "The Government May Want to Buy Your Dying Mall," 11 Sep. 2018 Lumber companies can sell some of the wood to recoup their expenses, but many of the trees are too decayed or structurally unsound to sell. Umair Irfan, Vox, "California has 129 million dead trees. That’s a huge wildfire risk.," 1 Sep. 2018 There's no hype for this adaptation of a schlocky 1997 novel about a scientifically unsound super-shark. Sam Machkovech, Ars Technica, "The Meg film review: We’re going to need a stupider boat," 10 Aug. 2018 Take it from one unsound sleeper: A little misting can go a long way. Brooke Bobb, Vogue, "5 Body Mists That Promise a Better Night’s Sleep—And Glowing Skin in the Morning," 29 July 2018 But the larger part for Democrats in Georgia is that their hope for revival is predicated on an unsound theory: That the level of Republican support among a shrinking percentage of white voters was relatively static. Chris Stirewalt, Fox News, "Georgia's disappointing Democrats," 22 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unsound.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of unsound

14th century, in the meaning defined above

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Statistics for unsound

Last Updated

3 Jul 2019

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Time Traveler for unsound

The first known use of unsound was in the 14th century

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More Definitions for unsound



English Language Learners Definition of unsound

: not based on truth or logic : not showing good judgment
: poorly built or in bad condition


un·​sound | \ ˌən-ˈsau̇nd How to pronounce unsound (audio) \

Kids Definition of unsound

1 : not based on good reasoning or truth an unsound argument unsound advice
2 : not firmly made or placed an unsound building
3 : not healthy or in good condition unsound teeth
4 : being or having a mind that is not normal


un·​sound | \ -ˈsau̇nd How to pronounce unsound (audio) \

Medical Definition of unsound

: not sound: as
a : not healthy or whole an unsound limb an unsound horse
b : not mentally normal : not wholly sane of unsound mind
c : not fit to be eaten unsound food

Other Words from unsound

unsoundness noun

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un·​sound | \ ˌən-ˈsau̇nd How to pronounce unsound (audio) \

Legal Definition of unsound

: not sound: as
a : not healthy or whole
b : not mentally normal : not wholly sane of unsound mind
c : not firmly made, placed, or fixed
d : not valid or true an unsound argument

Other Words from unsound

unsoundly adverb
unsoundness noun

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More from Merriam-Webster on unsound

Rhyming Dictionary: Words that rhyme with unsound

Thesaurus: All synonyms and antonyms for unsound

Spanish Central: Translation of unsound

Nglish: Translation of unsound for Spanish Speakers

Britannica English: Translation of unsound for Arabic Speakers

Comments on unsound

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food or victuals

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