certainly

adverb

cer·​tain·​ly ˈsər-tᵊn-lē 

1

: in a manner that is certain : with certainty

2

: it is certain that : assuredly

Synonyms of certainly

• definitely
• surely
• sure
• clearly
• probably
• really

Examples of certainly in a Sentence

It will certainly rain tomorrow.

This year's festival was certainly much better than last year's.

I'm certainly going to try.

The new version is most certainly easier to use.

The snake that bit her was almost certainly poisonous.

Recent Examples on the Web

While all of the remaining structures offer different services or wares than 70 years ago, some of them can certainly fit into your modern holiday with a little imagination. —Maggie Menderski, Louisville Courier Journal, 17 Dec. 2025

All of Clue’s scents are high art, a steering away from the path most trodden—and this one certainly embodies that ethos. —Adam Hurly, Robb Report, 17 Dec. 2025

Lucky 13 Swift’s favorite number is 13, a fact her fans would certainly note if Kelce has 52 total receiving yards before season’s end. —Pete Grathoff, Kansas City Star, 17 Dec. 2025

Tariffs are certainly closely tied to higher prices in this administration. —Domenico Montanaro, NPR, 17 Dec. 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing certainly

• certainly not

Rhymes for certainly

• uncertainly

Kids Definition

certainly

adverb

cer·​tain·​ly ˈsərt-ᵊn-lē 

1

: in a manner that is certain : for certain

the only event of which anything is certainly known

2

: without doubt : surely

certainly you can do it