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.
"From then 'til now I live with pain and incontinence and that's something that's really not talked about widely - with women generally, and certainly within certain communities."
From BBC • May 13, 2026
Admittedly, it isn’t a high-paying position, and it certainly isn’t the kind of internship that promises a leg up in future occupations.
From The Wall Street Journal • May 12, 2026
“The internet has certainly changed the way audiences connect with movies, for good and for bad. That can have an outsized impact,” the studio executive said.
From Los Angeles Times • May 12, 2026
It certainly wouldn’t be too hard to take the country.
From Salon • May 12, 2026
Ben certainly isn’t perfect—we all know he has a nasty temper.
From "The Wrong Way Home" by Kate O’Shaughnessy
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.
