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

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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

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Other Word Forms

• impossibleness noun
• impossibly adverb

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.

Example Sentences

Some executives privately expressed frustration with the administration’s optimistic message, adding that the uncertainty hanging over the conflict made it impossible to plan investments.

From The Wall Street Journal • Apr. 12, 2026

Chemists have achieved what many once considered impossible by stabilizing an extremely reactive molecule in water, confirming a 67-year-old theory about vitamin B1.

From Science Daily • Apr. 11, 2026

But fully turning the clock back will be well-nigh impossible.

From BBC • Apr. 10, 2026

But the exact effects are impossible to predict.

From Los Angeles Times • Apr. 10, 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

Related Words

• absurd
• futile
• hopeless
• impassable
• impractical
• inaccessible
• inconceivable
• insurmountable
• preposterous
• unattainable
• unimaginable
• unreasonable
• unthinkable
• unworkable
• useless