impossible

adjective

im·​pos·​si·​ble (ˌ)im-ˈpä-sə-bəl 

1

a

: incapable of being or of occurring

It's impossible to tell the future.

b

: felt to be incapable of being done, attained, or fulfilled : insuperably difficult

an impossible deadline

2

a

: extremely undesirable : unacceptable

in an impossible situation

b

: extremely awkward or difficult to deal with

The actor was impossible on the set.

impossibleness noun

Synonyms of impossible

• unlikely
• hopeless
• problematic
• impractical
• futile

Examples of impossible in a Sentence

It's impossible to predict the future.

The heavy rain made it impossible to see the road.

It's physically impossible for a child to lift that much at once.

It's virtually impossible to book a flight just before the holiday.

These math problems are impossible!

You refuse to help and then criticize me for not doing it right? You're impossible!

My boss is just an impossible woman.

Recent Examples on the Web

Your energy, self-confidence and competitive spirit are impossible to ignore, making this a powerful time for personal reinvention. — Valerie Mesa, PEOPLE, 26 June 2026

But survival there was impossible; like her cousin Kal-El, or Superman, before her, Kara was placed in a pod and catapulted to Earth for her safety, along with her scampish dog, Krypto. — Stephanie Zacharek, Time, 26 June 2026

On Thursday, the University of Kentucky announced a new $1 million prize to anyone able to decipher a complete scroll, a feat the researchers once considered impossible, by June next year. — Claudio Lavanga, NBC news, 26 June 2026

And if the source is an object that remains steady in brightness and doesn’t flare with activity, zeroing in on the neutrino’s origin feels impossible. — Ashley Strickland, CNN Money, 26 June 2026

Word History

Etymology

Middle English, from Anglo-French & Latin; Anglo-French, from Latin impossibilis, from in- + possibilis possible

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing impossible

• the impossible

Rhymes for impossible

• possible

Kids Definition

impossible

adjective

im·​pos·​si·​ble (ˈ)im-ˈpäs-ə-bəl 

1

a

: incapable of being or of occurring

b

: very difficult : hopeless

an impossible situation

2

: very bad or unpleasant

an impossible person

impossibly

-blē

adverb

Legal Definition

impossible

adjective

im·​pos·​si·​ble

: not possible : incapable of being done, attained, or fulfilled

a party's performance is impossible in part