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
Derived 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.
Even so, it was impossible to emerge from watching UFC Freedom 250 without feeling punch-drunk.
From Los Angeles Times • Jun. 15, 2026
"If this tree wasn't there, it'll be impossible for me to be here. The day this tree is gone, everything will be over."
From BBC • Jun. 15, 2026
And, in its own bloody way, MMA can be beautiful: humans in extremis, rising to the occasion, pushing past their own boundaries to accomplish the impossible under the most adverse of conditions.
From Slate • Jun. 14, 2026
Aside from its blockbuster spectacle, “Disclosure Day” is a pertinent reminder that, once we let go of our hope, it’s nearly impossible to get it back.
From Salon • Jun. 13, 2026
To demonstrate this, for the next minute, she proceeded to zip into invisible holes and then pop out of other holes at a speed nearly impossible to follow.
From "The Very, Very Far North" by Dan Bar-el
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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.