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

The Mets were in a similar situation last year, and ended up making an improbable run to the postseason. —Aaliyan Mohammed, MSNBC Newsweek, 23 Sep. 2025

Justin Herbert’s improbable escape and throw for a touchdown Sunday, when the Chargers needed greatness from their quarterback, stood out more than any other clutch play in Week 3. —Tom Krasovic, San Diego Union-Tribune, 22 Sep. 2025

Such an outcome might seem improbable, given historical trends and the political headwinds buffeting the White House. —David M. Drucker, Twin Cities, 19 Sep. 2025

Still others believe that empathy is a worthy ideal but an improbable one so long as working conditions in health care remain so bad. —Rachel Pearson, Harpers Magazine, 19 Sep. 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