certainly

adverb

cer·​tain·​ly ˈsər-tᵊn-lē 

1

: in a manner that is certain : with certainty

2

: it is certain that : assuredly

Synonyms

• all right
• alright
• assuredly
• clearly
• definitely
• doubtless
• easily
• forsooth
• hands down
• inarguably
• incontestably
• incontrovertibly
• indeed
• indisputably
• plainly
• really
• so
• sure
• surely
• truly
• unarguably
• undeniably
• undoubtedly
• unquestionably

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

Oscar Bobb generally gets far more assists than goals, too, but with those five players, as well as Rayan Cherki, City certainly have enough numbers for the wide roles, even if goals are not yet assured. —Dan Sheldon, New York Times, 22 June 2025

There is no overlap between the play and Aira’s life; certainly there’s no anger against the dying of the light in Aira. —Han Ong, New Yorker, 22 June 2025

And our prejudices and hierarchies will almost certainly follow us to the stars. —Robert Rubsam, The Atlantic, 21 June 2025

Suede shoes with a retro look seem to be particularly popular among fashion insiders around the world, though the color has certainly made its way to chunky iterations as well. —Emma Mehl, Glamour, 21 June 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