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.
Certainly, Coppins’ participation was something the editors wanted from the beginning; after taking on the story, the writer began outlining whom he would interview for the piece.
From Slate • May 5, 2026
"Certainly, that's a huge part of it," she says.
From BBC • May 2, 2026
Certainly in the long run, Dodger success is much more important to this engaged fan than the serial failure of a young player still playing like a rookie after two years.
From Los Angeles Times • May 2, 2026
Certainly different societies took different paths, on different time frames, but one is struck by how often they found similar solutions or ended up in the same place.
From The Wall Street Journal • May 1, 2026
“I know all about Mala. Her room is no place for a young girl. Certainly you cannot spend the night there.”
From "Homeless Bird" by Gloria Whelan
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.
