improbable

1 of 2

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

improbability

2 of 2

noun

im·​probability (¦)im 

əm+

1

: the quality or state of being improbable

questioned the improbability of a nuclear accident

2

: something improbable

Synonyms of improbable

Adjective

• unlikely

Examples of improbable in a Sentence

Adjective

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

Adjective

Her improbable success reflects a country on a political precipice. — Ryan Lenora Brown, Christian Science Monitor, 5 Nov. 2026

Slightly west, Sultan-Epe lies beside a deep canyon, where a stream threads through thickets of mulberry, buckthorn, blackberry, and wild herbs—another improbable pocket of green in one of Kazakhstan’s driest regions. — Avantika Chaturvedi, Architectural Digest, 5 Nov. 2026

Cutforth led the Broncos on an improbable comeback this past weekend against Texas State. — Shaun Goodwin, Idaho Statesman, 2 Nov. 2026

Valkyries owner Joe Lacob guaranteed a championship within the first five years for this franchise three years ago when the Bay Area was granted an expansion team, and in improbable, joyful fashion, his team accomplished it in Year 2. — Janie McCauley, Chicago Tribune, 1 Nov. 2026

Word History

Etymology

Adjective

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

First Known Use

Adjective

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