improbable

adjective

im·​prob·​a·​ble (ˌ)im-ˈprä-bə-bəl 

-ˈpräb-bəl

: unlikely to be true or to occur

also : unlikely but real or true

improbability

(ˌ)im-ˌprä-bə-ˈbi-lə-tē 

noun

improbably

(ˌ)im-ˈprä-bə-blē 

-ˈpräb-blē

adverb

Synonyms

• 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

Crooked Stick, the site of John Daly’s improbable 1991 PGA Championship win, returns to the list. —Tim Corlett, Forbes.com, 23 June 2025

Indiana had pulled off improbable comebacks all playoffs long. —Sean Gregory, Time, 23 June 2025

Trump’s decision to open a two-week negotiating window before deciding on striking Iran has offered a slim – if improbable – path to a peace deal between Iran and Israel. —Frederik Pleitgen, CNN Money, 20 June 2025

Their hero had delivered an improbable and unprecedented win for an MLS team over a European opponent in official competition. —Felipe Cardenas, New York Times, 20 June 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