certainty

noun

cer·​tain·​ty ˈsər-tᵊn-tē 

plural certainties

1

: something that is certain

2

: the quality or state of being certain especially on the basis of evidence

Synonyms

• assurance
• confidence
• satisfaction
• conviction

Choose the Right Synonym for certainty

certainty, certitude, conviction mean a state of being free from doubt.

certainty and certitude are very close; certainty may stress the existence of objective proof

claims that cannot be confirmed with scientific certainty

, while certitude may emphasize a faith in something not needing or not capable of proof.

believes with certitude in an afterlife

conviction applies especially to belief strongly held by an individual.

holds firm convictions on every issue

Examples of certainty in a Sentence

Scientists still do not know with any degree of certainty why the disease spread so quickly.

We cannot predict the outcome with absolute certainty.

There was no certainty that the package would arrive in time.

Her certainty about these complex moral issues is surprising.

Recent Examples on the Web

Advertisement While Gaal steels herself, the force that’s stalked her visions finally arrives, stepping into view with the certainty of someone who’s already seen the ending. —Jp Mangalindan, Time, 12 Sep. 2025

Traders also moved the probability of another reduction in October to a near certainty and see a high likelihood of a third move in December. —Jeff Cox, CNBC, 11 Sep. 2025

Too many RFPs seek certainty where little exists, which leads to unrealistic bids and a chain of costly change orders. —Ryan Gray, Forbes.com, 10 Sep. 2025

But getting certainty about what this rock truly contains likely requires hauling it off the Red Planet and delivering it back to Earth—an ambitious multiphase mission that NASA calls Mars Sample Return. —Humberto Basilio, Scientific American, 9 Sep. 2025

Word History

Etymology

Middle English certeinte, borrowed from Anglo-French certeinté, from certein, certain certain entry 1 + -té -ty

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing certainty

• almost a certainty
• with certainty

Rhymes for certainty

• uncertainty

Kids Definition

certainty

noun

cer·​tain·​ty ˈsərt-ᵊn-tē 

plural certainties

1

: something certain

2

: the quality or state of being or feeling certain