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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

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.

The "Mission: Impossible" star said Beckham's tenure in Los Angeles had been a huge part of the growth of football on this side of the Atlantic.

From Barron's • Jun. 12, 2026

There was no splashy Hollywood premiere like last year’s “Mission: Impossible — The Final Reckoning,” and there were only two American films in the prestigious main competition.

From The Wall Street Journal • May 23, 2026

The device was made at Pinewood studios by special effects engineers who won an Oscar for 1917 and who work on Star Wars, James Bond and Mission Impossible.

From BBC • May 22, 2026

“Piggy sees herself as Meryl Streep, but we see her differently. Fozzie thinks he’s John Mulaney. Gonzo feels he’s Tom Cruise in ‘Mission: Impossible.’

From Los Angeles Times • Feb. 4, 2026

I grab a napkin and begin a drawing of them for the Sketchbook of Impossible Things.

From "Fish in a Tree" by Lynda Mullaly Hunt

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