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

However, given the current circumstances with Kate undergoing cancer treatment and the family's appeal for privacy, expectations were uncertain. —Simon Perry, Peoplemag, 23 Apr. 2024

The national survey also found that American Jews are uncertain about their place in American society. —Jason Derose, NPR, 23 Apr. 2024

Formal complaint provides more details about why Landon Jacobs was dismissed Former AD declines teaching reassignment, uncertain about future Branham community strongly defends dismissed AD at school board meeting Longtime Branham AD loses his job. —Nathan Canilao, The Mercury News, 19 Apr. 2024

Sherrod Brown, who’s facing an uncertain reëlection campaign, came through East Palestine. —E. Tammy Kim, The New Yorker, 19 Apr. 2024

State legislative analysts were careful not to criticize policy choices made during the extraordinarily uncertain times. —Don Lee, Los Angeles Times, 18 Apr. 2024

The Charlotte Art League, after confronting months of leadership turmoil, financial worries, potential eviction and an uncertain future, now has a new executive director and new board of directors. —Catherine Muccigrosso, Charlotte Observer, 18 Apr. 2024

Now the Rubicon has been crossed, and the next chapter is uncertain and fraught with danger for Iran, its regime, and the broader region. —Ali Vaez, Foreign Affairs, 15 Apr. 2024

And all of that may continue despite the fact that the long-term risks of taking the drugs remain uncertain. —Gary Taubes, The Atlantic, 15 Apr. 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