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 While prices for certain imports like beef, coffee and tomatoes increased significantly last year, price hikes overall were little changed. Elisabeth Buchwald, CNN Money, 10 Jan. 2026 Because of this rare condition, superstitions and myths have permeated certain African countries, both positive and negative. Destiny Jackson, Deadline, 10 Jan. 2026 Some cruise lines also restrict certain areas of their ships to adults. Deirdre Bardolf, FOXNews.com, 10 Jan. 2026 Smith said that the increase in disaster costs is driven by greater exposure and vulnerability to extreme events, as well as by certain hazard types becoming more frequent or intense due to the influence of climate change. Doyle Rice, USA Today, 10 Jan. 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
  • Oddsmakers aren't so sure, making the white-hot and fifth-seeded Texans (12-5) the early favorite even though Houston has never won a road playoff game in its 24-year history.
    CBS News, CBS News, 6 Jan. 2026
  • Among the options were rib meat, pork, beef, chicken, no meat, and not sure, the lawyers wrote in the lawsuit.
    Marina Johnson, Louisville Courier Journal, 6 Jan. 2026
Adjective
  • Polk said the astronaut is stable but that diagnostic uncertainty in microgravity prompted NASA to err on the side of bringing the crew member back to Earth.
    Greg Wehner, FOXNews.com, 9 Jan. 2026
  • Treaties assume shared values, stable circumstances, and mutual benefit.
    Daniel Ross Goodman, The Washington Examiner, 9 Jan. 2026
Adjective
  • After giving birth to her second child in April, the 32-year-old was determined to continue breastfeeding her son — a choice that was both personally important and financially necessary for her family.
    Tereza Shkurtaj, PEOPLE, 9 Nov. 2025
  • The Federal Aviation Administration says the decision is necessary to keep travelers safe.
    Rio Yamat, Fortune, 9 Nov. 2025
Adjective
  • For decades, Venezuela was one of America's closest partners in Latin America, a reliable energy supplier, and a democracy that helped anchor the region.
    Arkansas Online, Arkansas Online, 9 Jan. 2026
  • Finding the right toiletry bag for your next trip is as important as buying a reliable carry-on or a hassle-free backpack.
    Michelle Baricevic, Travel + Leisure, 9 Jan. 2026
Adjective
  • The newest, pinkest addition to Orlando Auto Museum was a definite fixer-upper.
    Dewayne Bevil, The Orlando Sentinel, 8 Jan. 2026
  • The designer anticipates a definite shift from floral to geometric motifs, with bold color-blocking techniques that will set the tone in a room.
    Patricia Shannon, Better Homes & Gardens, 6 Jan. 2026
Adjective
  • The Dunning-Kruger effect is a cognitive bias in which people with less knowledge or skill feel overly confident.
    Dana Kelley, Arkansas Online, 9 Jan. 2026
  • On a crucial third-and-10 just inside field goal range, Beck was confident with his pass to Marion to get well within range.
    Scott Thompson, FOXNews.com, 9 Jan. 2026
Adjective
  • On third-and-1 with seven seconds left, Schakel took the snap and tried to spike the ball, which would have stopped the clock and given his team one final play to go for the win.
    Alex Valdes, New York Times, 9 Nov. 2025
  • After Flora’s go-ahead punt return score and Payne’s fumble, Becht had two important conversions on the Cyclones’ final drive.
    Steven Johnson, Fort Worth Star-Telegram, 9 Nov. 2025

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Cite this Entry

“Certain.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/certain. Accessed 11 Jan. 2026.

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