certainly

adverb

cer·​tain·​ly ˈsər-tᵊn-lē 

1

: in a manner that is certain : with certainty

2

: it is certain that : assuredly

Synonyms

• 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

Some will welcome it; there is certainly an argument that the attempts to imitate Guardiola’s style, playing from the back against high-class opponents with a plan to press them into mistakes, led to some coaches leading their teams like lambs to the slaughter. —Oliver Kay, New York Times, 16 Oct. 2025

There is certainly a skyrocketing amount of capital being put to work. —Sharon Goldman, Fortune, 15 Oct. 2025

With the relentless coverage of the Murdaughs on national news, and certainly amid the plethora of podcasts and docuseries, many of the details about the family and Maggie and Paul’s murderers have long been public knowledge. —Aramide Tinubu, Variety, 15 Oct. 2025

One good day in the stock market will not automatically change the fortunes of an entire sector, but the investor vibe certainly improved and momentum counts for something. —Evan Clark, Footwear News, 15 Oct. 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