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

There is nothing harder in sports right now than winning a Ryder Cup on the road, and New Yorkers will almost certainly make sure that reality remains intact. —Ian O'Connor, New York Times, 24 Sep. 2025

Weaver could certainly chat things up with his former team to ger some pointers on making the transition. —Andrew Wright, MSNBC Newsweek, 24 Sep. 2025

While Prohibition, which stretched from 1920 to 1933, certainly affected bowling alleys, especially the ones that served alcohol (which is to say, most of them), women started to bowl in greater numbers during that time. —The Editors, JSTOR Daily, 24 Sep. 2025

There’s certainly a case where purists may not like some, or all, of these changes. —Hayes Madsen, Rolling Stone, 24 Sep. 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