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

There are certainly areas for all parties to improve, Hernandez said. —Tim McDonnell, semafor.com, 23 Mar. 2026

These certainly aren’t the only proposals candidates have on the topic, or all the candidates who are running for governor, but rather just some of the ideas floated to voters recently. —Kaitlyn Schallhorn, Oc Register, 22 Mar. 2026

Kuminga has certainly shown signs of that with the Hawks, scoring 27, 17 and 20 points in his first three games with the Hawks. —Joseph Dycus, Mercury News, 22 Mar. 2026

There’s still a whole lot of 2026 left, but this could certainly end up being in my top five whiskeys of the year. —Jonah Flicker, Robb Report, 22 Mar. 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