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.
This and other secret projects are detailed in Josh Dean’s “The Impossible Factory.”
From The Wall Street Journal • May 18, 2026
Carl Tobias, Williams Chair in Law at the University of Richmond, told the BBC that Warsh faces a "Mission Impossible" when he takes on the job.
From BBC • May 13, 2026
Toward the book’s end they fantasize about a world in which your local Waffle House serves “mycelium-based steak and Impossible burgers for the patty melts,” with red meat unavailable at most restaurants.
From The Wall Street Journal • Apr. 17, 2026
At one man's request, the agency devised a "Mission Impossible" production for an adventurous young woman: an iPad delivered in the morning launched a scavenger hunt across Paris by sidecar and by boat.
From Barron's • Feb. 12, 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.