adverb
Etymology
Origin of certainly
Explanation
Use the adverb certainly when you’re sure about a particular action — absolutely, positively sure. If you love the new shoes you just bought, you may defend your purchase by saying they were certainly worth the money you paid. The word certainly emphasizes that you’re positive about something. When you hear thunder and look up at a gray sky, you might say it will certainly rain. If you’re on a diet, you could say that you will certainly avoid chocolate cake. Certainly can also be used to answer a question in the affirmative. If your boss asks to speak to you, you might answer, “Certainly.” It’s just a formal way of saying “yes.”
Vocabulary lists containing certainly
Florida's B.E.S.T. Common Suffixes: -ly
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"Alice's Adventures in Wonderland" by Lewis Carroll, Chapters 4–6
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Novel Study: Barrio Boy, Parts 1–3
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The argument wasn’t anything new, and it certainly wasn’t influenced by plateauing sales or consumer complaints.
From Salon • Jun. 14, 2026
The Americans certainly got a great start Friday, opening the second World Cup played on U.S. soil with a dominant 4-1 win over Paraguay.
From Los Angeles Times • Jun. 14, 2026
Well, there is certainly a sense within the camp that the team that started in Orlando, barring maybe one or two exceptions, will be the side that begins the tournament.
From BBC • Jun. 12, 2026
And the massive run-up in tech stocks since the end of the first quarter certainly hasn’t helped.
From Barron's • Jun. 12, 2026
There certainly had been a chance, but I didn’t feel regret.
From "Flying Through Water" by Mamle Wolo
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
