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 of certainty

• 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

By defining requirements upfront and approving change orders quickly, the model improves schedule certainty and ensures vessels are mission-ready when they are delivered. — Prabhat Ranjan Mishra, Interesting Engineering, 9 Oct. 2026

In emergency medicine, waiting for absolute certainty is not always the safer choice. — Dara Kass, Washington Post, 9 Oct. 2026

Heavy rainfall is a certainty with this storm, but the level of threat from sustained winds and storm surge will be dependent upon the extent to which Isaias can get its act together. — Eric Berger, ArsTechnica, 6 Oct. 2026

That certainty pushed them to do things unwise probably doesn’t go far enough to describe. — Bethy Squires, Vulture, 5 Oct. 2026

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