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

Recent Examples on the Web

Financial security is important not only for the future of the child, but also for mothers navigating the unpredictable complications of pregnancy. —Sunny Nagpaul, Fortune, 11 Apr. 2024

That concern comes amid hand-wringing in Washington and Tokyo over the possibility of a return to power by former President Donald J. Trump, whose unpredictable foreign policy has kept many world leaders on edge. —Michael D. Shear, New York Times, 10 Apr. 2024

That’s a mindset that would have come in handy for unpredictable food acquisition, like the sudden appearance of a herd of mammoths or an unexpected bounty of berries. —Popsci Staff, Popular Science, 10 Apr. 2024

Other research found that the pattern of grieving depended on the circumstances of how someone died, and that grief and acceptance rose and fell in an unpredictable way. —Angela Haupt, TIME, 10 Apr. 2024

And officials from both countries will look to lock in plans in case of an unpredictable U.S. president’s return. —Michelle Lee, Washington Post, 9 Apr. 2024

Life, with all its calibrations, turns on unpredictable things. —Jeffrey Fleishman, Los Angeles Times, 2 Apr. 2024

Wang suggested that, if anything, a Biden defeat may be preferable to Beijing, given Trump’s record of disruptive, unpredictable diplomacy. —Ishaan Tharoor, Washington Post, 29 Mar. 2024

But once a teenage Lynch began booking wrestling gigs around the world – first in the United Kingdom, Canada, the United States and then Japan before ultimately catching WWE’s attention in 2013 – Anne Quin began noticing her once unpredictable daughter was finally staying out of trouble. —Sean Neumann, Peoplemag, 27 Mar. 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