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.
Colbert named Pope Leo XIV as his dream guest for the finale, which is unlikely but certainly appropriate.
From Salon • May 21, 2026
Part of it is, if not quite cultural, then certainly aesthetic.
From The Wall Street Journal • May 21, 2026
Would I want to run an agency that’s currently in rough shape, that will certainly be blamed for enormous disasters to come if it can’t fulfill its responsibility?
From Slate • May 21, 2026
Lloyd's certainly made her home fans proud with her speed in the car, picking up her first F1 Academy victory in Saudi Arabia last year.
From BBC • May 21, 2026
It had certainly been an exciting morning for him, but a confusing one, too.
From "All About Sam" by Lois Lowry
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.
