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 result can be unpredictable outcomes that muddy accountability, require teams to retrace decisions and ultimately erode trust in the technology. — Ari Widlansky, Forbes.com, 1 Oct. 2026

Replaying that in the oceans would be dangerous and unpredictable. — Michael Albertus, Foreign Affairs, 30 Sep. 2026

As the Satanic Slasher gruesomely hacks his way across the country with the cop in pursuit, his backstory and intentions are parceled out to the viewer piece by piece, until the movie arrives at a completely unpredictable conclusion. — Jim Hemphill, IndieWire, 30 Sep. 2026

But new characters have the harder task of proving themselves to the audience; reality-TV charisma is an imprecise, unpredictable science. — Rafaela Bassili, Vulture, 29 Sep. 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