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

There is a contrarian streak that runs through John Bonner, a streak that takes the improbable and bends it to the possible — before bringing it to reality. —Brian Robin, Oc Register, 28 Jan. 2026

The hope that Legette can be a WR1 is over with Tetairoa McMillan in the picture, but even being the team's WR2 seems improbable. —Steve Bradshaw, Forbes.com, 27 Jan. 2026

Yet more squatters arrived, wedging homes and alleys into the most improbable gaps. —Sean Williams, Harpers Magazine, 27 Jan. 2026

But German defense outlays were notoriously parsimonious, and fast growth seemed improbable. —Gerry Doyle, Bloomberg, 27 Jan. 2026

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