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

First, D’Angelo Russell, at least for the moment remains with the Grizzlies, although a buyout or a waiver certainly is possible. — Ira Winderman, Sun Sentinel, 24 Sep. 2026

Guitarricadelafuente is certainly the strongest prospect of La Bola Negra’s male performers. — Scott Feinberg, HollywoodReporter, 24 Sep. 2026

So Coker’s decision-making ability as a punt returner will almost certainly be put to the test again. — Alex Zietlow, Charlotte Observer, 24 Sep. 2026

The Yankees may be down a few sluggers entering the postseason, however, they certainly are equipped with a player capable of picking up some of the slack. — James O'Connell, New York Daily News, 24 Sep. 2026

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