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

That has certainly been the case for some consumers, battered by inflation, tariffs and high borrowing costs that have sparked an affordability crisis. —Mari Sato The Dallas Morning News, Arkansas Online, 1 Feb. 2026

In the hours after Pretti was shot, Cook was at the location of the shooting, in the middle of the tear gas, offering legal help to anyone who needed it and bearing witness to conduct that will almost certainly face scrutiny one day, even if government leaders condone it now. —Los Angeles Times, 1 Feb. 2026

Yet, even though platonic vibes are certainly on the menu, romance and passion could also be manifesting from the universe before you, too. —Kyle Thomas, PEOPLE, 1 Feb. 2026

The organization, which strives to provide services to anyone who needs them, would almost certainly have to reduce hours or possibly even close clinics. —Orlando Sentinel Editorial Board, The Orlando Sentinel, 1 Feb. 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