Definition of certainnext
1
as in one
known but not named a certain person told me that today is your birthday

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

2
3
4
5
as in reliable
not likely to fail chicken soup is grandma's certain cure for pretty much whatever ails you

Synonyms & Similar Words

Antonyms & Near Antonyms

6

Synonym Chooser

How does the adjective certain contrast with its synonyms?

Some common synonyms of certain are cocksure, positive, and sure. While all these words mean "having no doubt or uncertainty," certain may apply to a basing of a conclusion or conviction on definite grounds or indubitable evidence.

police are certain about the cause of the fire

When would cocksure be a good substitute for certain?

In some situations, the words cocksure and certain are roughly equivalent. However, cocksure implies presumptuous or careless positiveness.

you're always so cocksure about everything

When is it sensible to use positive instead of certain?

While the synonyms positive and certain are close in meaning, positive intensifies sureness or certainty and may imply opinionated conviction or forceful expression of it.

I'm positive that's the person I saw

When could sure be used to replace certain?

The words sure and certain are synonyms, but do differ in nuance. Specifically, sure usually stresses the subjective or intuitive feeling of assurance.

felt sure that I had forgotten something

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of certain Carlos Ruiz Massieu, the head of the office, noted that despite security advances in certain areas of downtown Port-au-Prince, where security forces have intensified operations since December, the violence by armed groups remains a daily and unbearable reality for many Haitians. Jacqueline Charles, Miami Herald, 9 May 2026 The extent of redistricting in some states is still not certain. Larry Kaplow, NPR, 9 May 2026 For people who cannot or prefer not to use hormones, Colella says that non-hormonal medications such as certain antidepressants or blood pressure drugs may similarly help relieve hot flashes and improve mood symptoms. Daryl Austin, USA Today, 9 May 2026 Sometimes Redick’s tasks are simply checking in with certain players. Los Angeles Times, 9 May 2026 See All Example Sentences for certain
Recent Examples of Synonyms for certain
Adjective
  • Drinkwater didn't make one appearance in a Chelsea shirt last season, whilst Bakayoko spent the season in Italy on loan at AC Milan.
    SI.com, SI.com, 3 Aug. 2019
  • Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive.
    Johannes Himmelreich, BostonGlobe.com, 30 Mar. 2018
Adjective
  • Once the game was knotted up at three, Bennett settled down and made sure to keep it that way.
    Mac Cerullo, Boston Herald, 8 May 2026
  • There's quite a bit of variety between the different buildings so be sure to specify and ask questions when booking.
    Condé Nast, Condé Nast Traveler, 7 May 2026
Adjective
  • The bigger lesson from the Strait of Hormuz crisis is that efficiency may work in a stable world, but falls apart in an unstable one.
    Victor Nian, Fortune, 10 May 2026
  • Chinese state media said the robots can navigate difficult terrain and operate as stable mobile weapons platforms resistant to recoil and blast impacts.
    Bojan Stojkovski, Interesting Engineering, 10 May 2026
Adjective
  • Manager Dave Roberts continues to marvel at the veteran of 17 seasons who is willing to make whatever change is necessary to remain a productive hitter.
    Doug Padilla, Oc Register, 9 May 2026
  • On balance, confronting Iran’s nuclear ambitions was necessary.
    Lucas Robinson, San Diego Union-Tribune, 8 May 2026
Adjective
  • Even recognizing one or two reliable triggers—like tight clothing, prolonged sitting or hot weather—can help guide meaningful adjustments.
    Lauryn Higgins, Flow Space, 11 May 2026
  • The dogs provide rangers with a reliable way to etch trails, haul supplies and even assist park scientists with snow-dependent research.
    K. R. Callaway, Scientific American, 11 May 2026
Adjective
  • From California to Annecy, Walt Disney Animation Studios and Pixar Animation Studios will travel with two back-to-back presentations, a definite highlight of Annecy’s Friday in recent years.
    Kevin Giraud, Variety, 28 Apr. 2026
  • Getting Clardy is a definite positive.
    Chantel Jennings, New York Times, 28 Apr. 2026
Adjective
  • In…early books, Strout seemed confident that good would eventually prevail, or at least persist.
    Literary Hub, Literary Hub, 7 May 2026
  • If the Leafs take Stenberg, and the Sharks want a defenseman and are confident that the Vancouver Canucks will select McKenna, maybe the two Pacific Division teams can arrange a trade.
    Curtis Pashelka, Mercury News, 7 May 2026
Adjective
  • As the Timberwolves desperately searched for an equalizer in the final five minutes, Notre Dame goaltender Kendra DeLawter stood tall in net, robbing two point-blank attempts to preserve the lead for the Cougars.
    Brendan Connelly, Boston Herald, 9 May 2026
  • Leading 4-1 in the fourth, the Falcons had runners on first and second with one out and a chance to extend the lead, but Bram Schwartz came out of the bullpen to get the final two outs, and then pitch a scoreless fifth.
    John Maffei, San Diego Union-Tribune, 9 May 2026

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Cite this Entry

“Certain.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/certain. Accessed 12 May. 2026.

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