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 Cardinals won an improbable World Series because Freese did those things. —Jayson Stark, New York Times, 29 Sep. 2025

The Cleveland Guardians completed their remarkable September surge on Saturday, clinching an improbable playoff berth after beating the Texas Rangers 3-2 on a walk-off hit by pitch. —Mac Cerullo, Boston Herald, 28 Sep. 2025

What seemed improbable just a week ago now seems entirely possible for the New York Yankees. —Jackson Roberts, MSNBC Newsweek, 24 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

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