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Synonyms

certainly

American  
[sur-tn-lee] / ˈsɜr tn li /

adverb

  1. with certainty; without doubt; assuredly.

    I'll certainly be there.

  2. yes, of course.

    Certainly, take the keys.

  3. to be sure; surely.

    He certainly is successful.
certainly British  
/ ˈsɜːtənlɪ /

adverb

  1. with certainty; without doubt

    he certainly rides very well
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

  1. by all means; definitely: used in answer to questions

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of certainly

First recorded in 1250–1300; Middle English; certain + -ly

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.

“And high asset prices, which certainly feel good in the short run, create additional risk if anything goes wrong,” Dimon says.

From The Wall Street Journal • Apr. 6, 2026

Flores was certainly the more active but few of those shots found the target as Scotney threw with precision and purpose - doing the cleaner work.

From BBC • Apr. 5, 2026

Instead, Clement almost certainly meant former New York City mayor Rudy Giuliani, who was considered the frontrunner for the 2008 Republican presidential nomination at the time.

From Salon • Apr. 4, 2026

Given the points system used to determine starters in the Kentucky Derby, Intrepido almost certainly needs to finish first or second Saturday at Santa Anita.

From Los Angeles Times • Apr. 4, 2026

“Well, we certainly don’t want that to happen,” said Handsome, pulling himself together.

From "The Very, Very Far North" by Dan Bar-el

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.