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

The vast differences and gaps are indisputable, but not unpredictable. — Dana Kelley, Arkansas Online, 13 Nov. 2026

Perhaps the arrival of fall and winter, and with it rougher and more unpredictable seas, will reduce the flow. — Pedro Portal, Miami Herald, 12 Nov. 2026

Potential applications include manufacturing, space exploration and search-and-rescue missions, where robots may need to navigate unpredictable environments, manipulate objects and adapt to changing requirements. — Jijo Malayil, Interesting Engineering, 12 Nov. 2026

But attracting audiences, Fahmy acknowledges, is an increasingly unpredictable undertaking. — Essie Assibu, Variety, 12 Nov. 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