uncertain

adjective

un·​cer·​tain ˌən-ˈsər-tᵊn 

1

a

: not known beyond doubt : dubious

an uncertain claim

b

: not having certain knowledge : doubtful

remains uncertain about her plans

c

: not clearly identified or defined

a fire of uncertain origin

2

: not constant : variable, fitful

an uncertain breeze

3

: indefinite, indeterminate

the time of departure is uncertain

4

: not certain to occur : problematical

his success was uncertain

5

: not reliable : untrustworthy

an uncertain ally

uncertainly adverb

uncertainness

ˌən-ˈsər-tᵊn-(n)əs 

noun

Synonyms

• capricious
• changeable
• changeful
• fickle
• flickery
• fluctuating
• fluid
• inconsistent
• inconstant
• mercurial
• mutable
• skittish
• temperamental
• unpredictable
• unsettled
• unstable
• unsteady
• variable
• volatile

Examples of uncertain in a Sentence

The time of departure is still uncertain.

We are still uncertain of the truth.

She remains uncertain about her plans.

I'm uncertain about how to respond.

The cause of the fire is uncertain.

He has an uncertain temper.

They face a financially uncertain future.

Recent Examples on the Web

Another installment in the Kingsman franchise, which first launched Egerton’s career with 2014’s Kingsman: The Secret Service, is uncertain. —Jack Smart, People.com, 10 Dec. 2024

Can Raw Milk Give You Bird Flu? The effects of drinking raw milk tainted with bird flu are still uncertain. —Katherine Hignett, Forbes, 9 Dec. 2024

But Steinbach said the potential effects on farms’ water use, both regionally and statewide, are uncertain and will depend on a complex mix of factors. —Ian James, Los Angeles Times, 8 Dec. 2024

Pickens' status has been uncertain and ESPN's Adam Schefter speculated that a pregame warmup will be the final factor in determining his availability for the game. —Daniel R. Depetris, Newsweek, 8 Dec. 2024

Word History

First Known Use

14th century, in the meaning defined at sense 3

Phrases Containing uncertain

• in no uncertain terms

Kids Definition

uncertain

adjective

un·​cer·​tain ˌən-ˈsərt-ᵊn 

ˈən-

1

: not definite or fixed

an uncertain quantity

2

a

: not sure

uncertain of the truth

b

: not known for sure

an uncertain claim

3

: likely to change : not dependable

uncertain weather

uncertainly adverb