unsound
Americanadjective
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not sound; unhealthy, diseased, or disordered, as the body or mind.
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decayed or impaired, as timber or foods; defective.
- Synonyms:
- unwholesome, rotten
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not solid or firm, as foundations.
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not well-founded or valid; fallacious.
an unsound argument.
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easily broken; light.
unsound slumber.
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not financially strong; unreliable.
an unsound corporation.
adjective
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diseased, weak, or unstable
of unsound mind
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unreliable or fallacious
unsound advice
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lacking solidity, strength, or firmness
unsound foundations
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of doubtful financial or commercial viability
an unsound enterprise
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(of fruit, timber, etc) not in an edible or usable condition
Other Word Forms
- unsoundly adverb
- unsoundness noun
Etymology
Origin of unsound
Middle English word dating back to 1275–1325; un- 1, sound 2
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
She’s right about that, but this manual included some unsound science.
From The Wall Street Journal • Feb. 8, 2026
He has said the city government has "grave concerns" about any deployment of troops, labelling the president's approach as "uncoordinated, uncalled for, and unsound".
From BBC • Aug. 24, 2025
Then, following the 1971 Sylmar earthquake, the Wadsworth Hospital building was judged seismically unsound and demolished.
From Los Angeles Times • Aug. 5, 2024
The judge pointed out that there was no evidence to support that theory, and he faulted the prosecutors for legally unsound charges, like alleging assault while making claims about actions merely being negligent.
From Slate • May 9, 2024
It worked in their second game, when the little man overreached himself with an unsound assault.
From "A Dance with Dragons" by George R. R. Martin
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.