impossible
Americanadjective
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not possible; unable to be, exist, happen, etc.
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unable to be done, performed, effected, etc..
an impossible assignment.
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incapable of being true, as a rumor.
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not to be done, endured, etc., with any degree of reason or propriety.
an impossible situation.
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utterly impracticable.
an impossible plan.
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hopelessly unsuitable, difficult, or objectionable.
- Synonyms:
- unmanageable, intolerable, unbearable
adjective
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incapable of being done, undertaken, or experienced
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incapable of occurring or happening
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absurd or inconceivable; unreasonable
it's impossible to think of him as a bishop
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informal intolerable; outrageous
those children are impossible
Other Word Forms
Etymology
Origin of impossible
First recorded in 1250–1300; Middle English word from Latin word impossibilis. See im- 2, possible
Explanation
Something that's impossible can't be done. If you want to stop eating donuts but you just can't, you might say it's impossible. If it's impossible, it cannot happen, or it doesn't exist. You might wish you could bring Abraham Lincoln back to life for a day so he could come to tea, but that's impossible. People use the word impossible to mean "out of reach" or "too hard to achieve." A terrible situation can be impossible, and so can a person who refuses to compromise or seems intent on making things difficult for everyone else.
Vocabulary lists containing impossible
List 1
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myPerspectives 7.3
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im-
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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.
The “Satyagraha” and “Akhnaten” revivals have been the designed-to-dazzle inventions of quirky director Phelim McDermott, a co-founder of Impossible, an eccentric British theater company.
From Los Angeles Times • Mar. 5, 2026
Beyond that looms pension reform, the Mission Impossible for all democratic governments.
From Barron's • Feb. 26, 2026
McGuinness will remain on the company’s board, Impossible Foods said.
From The Wall Street Journal • Jan. 30, 2026
Cruise spent the first two decades of his career stretching himself artistically, never making a sequel until 2000’s “Mission: Impossible II.”
From Los Angeles Times • Jan. 1, 2026
Impossible to tell whether or not he meant it.
From "The Handmaid's Tale" by Margaret Atwood
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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.