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
Etymology
Origin of unsound
Middle English word dating back to 1275–1325; see origin at 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.
See Examples For:
If the proof is unverified by humans and the pure math is shaky, the applied math built on it can be not only unsound but dangerous.
From The Wall Street Journal ● Jun. 14, 2026
Germany is uniquely neurotic about debt and about unsound money.
From BBC ● Mar. 27, 2026
I joke to Shires that, as a man, most often the unsound advice I have received is to simply go look for a rebound.
From Los Angeles Times ● Sep. 29, 2025
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
Bishop Colenso, whose views on everything were considered unsound that day and are archaic in this, was the little dean’s particular pet.
From "Go Set a Watchman: A Novel" by Harper Lee
At once the unsoundest and the most attractive argument is to be found in the deliberate idealization of particular ages, the thirteenth century in England, for example, or the age of the Antonines.
From New Worlds For Old A Plain Account of Modern Socialism by Wells, H. G. (Herbert George)
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.
