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

Best times to view the comet Comets can be unpredictable. —Janet Loehrke, USA TODAY, 4 Oct. 2024

But the reality is, late movement in the race can be unpredictable, and the winner hasn’t been determined yet. —Mary Radcliffe, ABC News, 4 Oct. 2024

Life is unpredictable, and flexibility is key to handling the unexpected while staying on track. —Benjamin Laker, Forbes, 4 Oct. 2024

The health outlook becomes infinitely more complex and the cancer more unpredictable, which can trigger great stress for patients. —Karthika Gupta, People.com, 2 Oct. 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