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

The Outlaw Music Festival touched down Thursday night on the North Island Credit Union Amphitheatre in Chula Vista, California, and Bob Dylan once again delivered a wildly unpredictable set that stunned even his most hardcore fans. —Andy Greene, Rolling Stone, 16 May 2025

Markets are unpredictable, and a company's success doesn't ensure future returns. —Mike Winters, CNBC, 15 May 2025

Another plus: The votes were completely unpredictable from week to week, leading to some truly crazy Tribals. —Dalton Ross, EW.com, 15 May 2025

This winding road to diagnosis, although uncertain and unpredictable, has taught me to continue speaking up and pushing for answers. —Racquel H. Dozier, Health, 14 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