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

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.

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.

Even so, it was impossible to emerge from watching UFC Freedom 250 without feeling punch-drunk.

From Los Angeles Times • Jun. 15, 2026

It's impossible not to notice the shift in the ever stoic Clarke.

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

His scrappy, mostly lost first feature, “Firelight,” was about pursuing alien life to prove that the impossible is very much possible.

From Salon • Jun. 13, 2026

By late afternoon there was a full storm blowing snow so hard it was impossible to see where we were going.

From "Woodsong" by Gary Paulsen

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