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

The addition of glass tubes certainly adds another dimension to both sparse and dense arrangements. —Miles Socha, Footwear News, 17 May 2025

This means, under the current rules at least, a return to the United States, just 12 years after the men’s World Cup in 2026 and (almost certainly) the women’s World Cup in 2031, may well be the likeliest outcome if FIFA enforces the principle. —Adam Crafton, New York Times, 17 May 2025

But Ian’s foot is certainly more active at some times than others. —Sarah Zhang, The Atlantic, 16 May 2025

Thursday certainly made for a refreshing change of pace from Games 1-5, in which OKC's bench had averaged 34 points to the Nuggets' 22 and made four more 3s per contest (6.8 vs. 2.8). —Sean Keeler, Denver Post, 16 May 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