impossibility

noun

im·​pos·​si·​bil·​i·​ty (ˌ)im-ˌpä-sə-ˈbi-lə-tē 

1

: the quality or state of being impossible

the impossibility of knowing the future

2

: something impossible

The snowstorm made travel an impossibility.

Examples of impossibility in a Sentence

The blizzard made travel an impossibility.

the impossibility of knowing what the future will bring

Recent Examples on the Web

That is a mathematical impossibility. —Charlie Fink, Forbes.com, 24 Jan. 2026

The book picks up in the aftermath, leading you no closer to an absolute answer but through the tangled impossibility of ever fully knowing another person. —Chloe Schama, Vogue, 24 Jan. 2026

However, detecting a single graviton was mostly dismissed as an experimental impossibility, leaving the bridge between these two theories purely speculative. —Mrigakshi Dixit, Interesting Engineering, 16 Jan. 2026

The seeming impossibility of Shane and Ilya’s homosexual love affair makes for an enjoyable sort of narrative edging. —Naomi Fry, New Yorker, 10 Jan. 2026

Word History

First Known Use

14th century, in the meaning defined at sense 1

Rhymes for impossibility

• acceptability
• accessibility
• adaptability
• admissibility
• advisability
• affordability
• allowability
• amenability
• amiability
• appealability
• applicability
• availability

Kids Definition

impossibility

noun

im·​pos·​si·​bil·​i·​ty (ˌ)im-ˌpäs-ə-ˈbil-ət-ē 

plural impossibilities

1

: the quality or state of being impossible

2

: something impossible

Legal Definition

impossibility

noun

im·​pos·​si·​bil·​i·​ty

plural impossibilities

1

: the quality or state of being impossible

also : the affirmative defense that something (as performance) is impossible

2

: something impossible

3

: impossibility of performance in this entry

— factual impossibility

: impossibility based on factual circumstances

specifically : a partial defense to criminal liability based on the incompletion of an intended criminal act

Note: Factual impossibility is not a complete defense and does allow prosecution for attempt or for another inchoate offense. For example, if the defendant constructed a bomb that failed to explode, factual impossibility would be a defense against murder charges, but not attempted murder.

— impossibility of performance

: a doctrine in contract law that a party may be released from liability for breach of contract for failing to perform an obligation that is rendered impossible by uncontrollable circumstances (as death or failure of the means of delivery)

: a defense to breach of contract or a basis for release from contractual obligations because of impossibility of performance compare frustration, impracticability

— legal impossibility

: impossibility based on or with reference to a law

specifically : a complete defense to criminal liability based on the commitment of acts that are not criminal or illegal

Note: Legal impossibility is founded on the principle that an act is not a crime unless there is a law prohibiting it.