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Synonyms

impossible

American  
[im-pos-uh-buhl] / ɪmˈpɒs ə bəl /

adjective

  1. not possible; unable to be, exist, happen, etc.

  2. unable to be done, performed, effected, etc..

    an impossible assignment.

  3. incapable of being true, as a rumor.

  4. not to be done, endured, etc., with any degree of reason or propriety.

    an impossible situation.

  5. utterly impracticable.

    an impossible plan.

  6. hopelessly unsuitable, difficult, or objectionable.

    Synonyms:
    unmanageable, intolerable, unbearable

impossible British  
/ ɪmˈpɒsəbəl /

adjective

  1. incapable of being done, undertaken, or experienced

  2. incapable of occurring or happening

  3. absurd or inconceivable; unreasonable

    it's impossible to think of him as a bishop

  4. informal intolerable; outrageous

    those children are impossible

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.

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Vocabulary lists containing impossible

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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