certainly

adverb

cer·​tain·​ly ˈsər-tᵊn-lē How to pronounce certainly (audio)
Synonyms of certainly
1
: in a manner that is certain : with certainty
2
: it is certain that : assuredly

Synonyms of certainly

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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.
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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The Ocean & Harvest Spa is certainly a can't-miss, with an indoor pool, gym and fitness classes, and of course, the spa itself, where massages, facials, and hair and nail services can be booked. — Condé Nast, Condé Nast Traveler, 30 Oct. 2026 The Green Bay Packers are certainly looking to move the ball through the air. — Outkick, FOXNews.com, 29 Oct. 2026 Adding Gwath, who had 68 blocks as a freshman and 37 as a sophomore and moves well, certainly boosts that goal, and Gwath thinks the team’s length and experience should help on defense. — Colleen Kane, Chicago Tribune, 29 Oct. 2026 Landing on the Moon is wholly tangential to the company’s near-term AI future, and fulfilling the contract will almost certainly be a net negative from a financial perspective. — Eric Berger, ArsTechnica, 29 Oct. 2026 See All Example Sentences for certainly

Word History

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of certainly was in the 14th century

Phrases Containing certainly

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certain
certainly
certainly not
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Cite this Entry

“Certainly.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/certainly. Accessed 1 Nov. 2026.

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Kids Definition

certainly

adverb
cer·​tain·​ly ˈsərt-ᵊn-lē How to pronounce certainly (audio)
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
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