unpredictable

adjective

un·​pre·​dict·​able ˌən-pri-ˈdik-tə-bəl 

: not predictable: such as

a

: not able to be known or declared in advance

unpredictable weather

b

: tending to behave in ways that cannot be predicted

an unpredictable boss

unpredictably

ˌən-pri-ˈdik-tə-blē 

adverb

changes that occur unpredictably

unpredictability

ˌən-pri-ˌdik-tə-ˈbi-lə-tē 

noun

the unpredictability of the weather

Synonyms

• capricious
• changeable
• changeful
• fickle
• flickery
• fluctuating
• fluid
• inconsistent
• inconstant
• mercurial
• mutable
• skittish
• temperamental
• uncertain
• unsettled
• unstable
• unsteady
• variable
• volatile

Examples of unpredictable in a Sentence

unpredictable spring weather that makes it really hard to know what to wear

Recent Examples on the Web

As federal environmental policy undergoes rapid and often unpredictable shifts through reversals, reinterpretations and sometimes outright dismantling, businesses are left navigating a compliance landscape that feels more like quicksand than solid ground. —John F. McQuillan, Forbes.com, 27 May 2025

John Daly and Tiger Woods share a legendary and unpredictable bond. —Devlina Sarkar, MSNBC Newsweek, 27 May 2025

Smaller airlines are reportedly being hurt worst by unpredictable travel times. —Brian Niemietz, New York Daily News, 27 May 2025

Trump’s aggressive and unpredictable policies — including massive import taxes — have clouded the outlook for the economy as well as the job market and raised fears that the American economy is headed toward recession. —Matt Ott, Chicago Tribune, 27 May 2025

Word History

First Known Use

1840, in the meaning defined above

Rhymes for unpredictable

• indictable
• predictable

Kids Definition

unpredictable

adjective

un·​pre·​dict·​able

ˌən-pri-ˈdik-tə-bəl

: not predictable

unpredictability

-ˌdik-tə-ˈbil-ət-ē

noun

unpredictably

-ˈdik-tə-blē

adverb