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

Laws and norms govern their actions to a degree but the human element is unpredictable. —Richard Bishop, Forbes, 16 Jan. 2025

Their shifts are relatively short, four hours in the air followed by eight on the ground to try to recover, but the winds remain unpredictable and the flights incredibly intense. —Grace Toohey, Los Angeles Times, 15 Jan. 2025

On top of this, issues related to money and possessions are unpredictable. —Georgia Nicols, The Denver Post, 15 Jan. 2025

The cornerback room outside of Pro Bowler Jaycee Horn and No. 2 guy Mike Jackson was unpredictable. —Alex Zietlow, Charlotte Observer, 14 Jan. 2025

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