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

Cape Hatteras National Seashore The iconic black-and-white spiral striped lighthouse on the Cape Hatteras National Seashore has certainly graced its fair share of postcards and screensavers—but there’s nothing quite like seeing it in person. —Tara Massouleh McCay, Southern Living, 22 Feb. 2025

Plus, the Reed Arena home advantage is certainly palpable. —Steven Louis Goldstein, The Athletic, 22 Feb. 2025

Well, the stats certainly say yes, at least internationally. —Tom Rogers, Newsweek, 22 Feb. 2025

However, while this dominance is certainly an asset, it can also be viewed as a liability by some, mainly the U.S. Department of Justice. —Kenneth Squire, CNBC, 22 Feb. 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