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

And the Shillings certainly weren’t happy with the amount. —Tresa Baldas, Freep.com, 22 Aug. 2025

Keys’ career certainly hit its high point this past year, with her big win at the Australian Open. —Andy Frye, Forbes.com, 22 Aug. 2025

Other Yankees tried to downplay the matchup, but the club is certainly looking for a few wins after going 1-5 against the Red Sox earlier this season. —Gary Phillips, New York Daily News, 21 Aug. 2025

Using him as trade bait certainly isn't in the plans. —Justin Grasso, MSNBC Newsweek, 21 Aug. 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