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
• unstable
• changeful

Examples of unpredictable in a Sentence

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

Recent Examples on the Web

Peak fall color is still potential to be realized, a brilliance whose arrival is impending but unpredictable. — Dana Kelley, Arkansas Online, 16 Oct. 2026

So put a monitoring system in place to avoid surprises, as much as possible, from an unpredictable colleague. — Dorie Clark, Contributor, CNBC, 15 Oct. 2026

In Melrose Hill, Chainsaw Cafe is a charming, unpredictable micro cafe with a tight menu of arepas, coffee and stellar desserts. — Jenn Harris, Los Angeles Times, 15 Oct. 2026

Loos, who was thirty-one, was known to express displeasure in hot and angry bursts and could be unpredictable. — Literary Hub, 14 Oct. 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