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

However, logistical challenges, such as unpredictable weather, play a role in these considerations. —Thomas G. Moukawsher, Newsweek, 17 Dec. 2024

Success, the author argues, is primarily the product of unpredictable social processes, support from famous sponsors, and a perfect match with the zeitgeist. —Christian Stadler, Forbes, 16 Dec. 2024

Lofoten mountain biking trails Though known for unpredictable weather year-round, the islands are driest May through August and get drenched in October. —Alexandra Gillespie, Outside Online, 16 Dec. 2024

On the one hand, the month and a half post-election can seem like decades, as D.C.’s political class awaits the unpredictable transition of power. —Hanna Trudo, The Hill, 15 Dec. 2024

Word History

First Known Use

1840, in the meaning defined above

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