Dictionary.com
Thesaurus.com
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.

Keep Reading on Vocabulary.com

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.

"We have almost nothing left, it's impossible to even find an egg," Sheyla Caya, 43, told AFP as she queued to buy a chicken.

From Barron's • May 20, 2026

Tireless, independent, efficient and available, AI systems can now measure an organization with a level of objective detail and precision that was previously impossible even for the best employees.

From The Wall Street Journal • May 20, 2026

A generation ago, that would have been impossible.

From Slate • May 20, 2026

But today, with essentially zero funding for such efforts, it’s impossible to mount anything close to the same response, which may allow outbreaks to surge and spread further.

From Salon • May 20, 2026

It was impossible to recognize that stooped and shabby little man in the glorious figure at the door, greeting newcomers with a formal welcome followed by a relentless tour of the shop.

From "The Hiding Place" by Corrie ten Boom

Vocabulary.com logo
by dictionary.com

Look it up. Learn it forever.

Remember "impossible" for good with VocabTrainer. Expand your vocabulary effortlessly with personalized learning tools that adapt to your goals.

Take me to Vocabulary.com