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

Bryce Underwood launched a Hail Mary well out of the end zone as time seemed to expire on the Wolverines to give WMU an improbable upset victory late Saturday night in Ann Arbor. — Austin Meek, New York Times, 6 Sep. 2026

The interaction feels wildly improbable even with respect to a movie that doesn’t claim to create a probable world. — Ryan Lattanzio, IndieWire, 4 Sep. 2026

The most improbable player to win a spot on the Miami’s 53 man roster didn’t merely defy the odds by sticking as an undrafted rookie, the only one of more than a dozen Dolphins to do that. — Barry Jackson, Miami Herald, 3 Sep. 2026

He’s recruited by a manipulative former acquaintance (Matthew Goode) and a siren with the improbable name of Luvlee Lemons (Isla Fisher) to steal a fortune from a local bank. — Declan Gallagher, Entertainment Weekly, 3 Sep. 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