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

This enabled them to analyze thousands of frames, each showing every atom’s position, which would be nearly impossible for humans to track manually. —Christopher McFadden, Interesting Engineering, 6 Dec. 2025

With workloads that vary depending on the rotation, going to sleep and waking up at a consistent time is impossible. —Terry Ward, CNN Money, 6 Dec. 2025

During the developing and drying stages, the residual chemistry of the dyes continues to act on the surface, creating textures and tones that are entirely unique and impossible to replicate. —Photovogue, Vogue, 5 Dec. 2025

Choosing the unfortunate 10% of kids who should make the fateful trip to outer space is an impossible task — Thanos's finger snap was so much easier — but the politicians hardly cover themselves in glory. —Richard Edwards, Space.com, 5 Dec. 2025

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