improbable

adjective

im·​prob·​a·​ble (ˌ)im-ˈprä-bə-bəl 

-ˈpräb-bəl

: unlikely to be true or to occur

an improbable story

also : unlikely but real or true

their improbable come-from-behind victory

improbability

(ˌ)im-ˌprä-bə-ˈbi-lə-tē 

noun

improbably

(ˌ)im-ˈprä-bə-blē 

-ˈpräb-blē

adverb

Synonyms of improbable

• unlikely

Examples of improbable in a Sentence

The team made an improbable comeback.

it seems improbable that the two writers never met since they traveled in the same social circles

Recent Examples on the Web

As the investigation continues, scientists are weighing a series of improbable scenarios, from space rocks to space junk, in hopes of identifying what exactly fell from the sky onto a moving Tesla in the South Australian night. —Kaif Shaikh, Interesting Engineering, 3 Nov. 2025

During the Mahomes era, the Chiefs have defied the odds several times to capture improbable victories. —Blair Kerkhoff, Kansas City Star, 3 Nov. 2025

Then Christina arrived, chic and funny, my improbable daughter-in-law. —James Marcus, New Yorker, 3 Nov. 2025

That set off an improbable four-point swing made possible by Jags kicker Cam Little’s field goal as time expired — from 68 yards, an NFL record. —Michael Silver, New York Times, 3 Nov. 2025

Word History

Etymology

Middle French or Latin; Middle French, from Latin improbabilis, from in- + probabilis probable

First Known Use

1598, in the meaning defined above

Rhymes for improbable

• probable

Kids Definition

improbable

adjective

im·​prob·​a·​ble (ˈ)im-ˈpräb(-ə)-bəl 

: not probable : unlikely to be true or to occur

improbability

(ˌ)im-ˌpräb-ə-ˈbil-ət-ē 

noun

improbably

(ˈ)im-ˈpräb(-ə)-blē 

adverb