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 of unpredictable

• volatile
• changeful
• unstable

Examples of unpredictable in a Sentence

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

Recent Examples on the Web

Authorities urged people to be prepared to stay away for several days, because shifting and strengthening winds were expected to make the fire even more unpredictable. — ABC News, 23 Aug. 2026

Weather conditions up the mountain can also be unpredictable. — Chris Lau, CNN Money, 23 Aug. 2026

The result is a collection that can feel meticulously curated one moment and completely unpredictable the next. — Tiana Randall, Forbes.com, 22 Aug. 2026

Fisher, 50, says this scene was the most challenging to film, thanks to her unpredictable, four-legged costars. — Erin Jensen, USA Today, 22 Aug. 2026

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