certain

American  

[sur-tn] / ˈsɜr tn /

adjective

1. free from doubt or reservation; confident; sure.

   I am certain he will come.

   Synonyms:

   satisfied

2. destined; sure to happen (usually followed by an infinitive).

   He is certain to be there.

3. inevitable; bound to come.

   They realized then that war was certain.

4. established as true or sure; unquestionable; indisputable.

   It is certain that he tried.

   Synonyms:

   clear, plain, obvious, incontrovertible, irrefutable, incontestable, indubitable

5. fixed; agreed upon; settled.

   on a certain day; for a certain amount.

   Synonyms:

   determined

6. definite or particular, but not named or specified.

   A certain person phoned. He had a certain charm.

7. that may be depended on; trustworthy; unfailing; reliable.

   His aim was certain.

8. some though not much.

   a certain reluctance.

9. Obsolete. steadfast.

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pronoun

1. certain ones.

   Certain of the members declined the invitation.

idioms

1. for certain, without a doubt; surely.

   I know for certain that I have seen that face before.

certain British  

/ ˈsɜːtən /

adjective

1. (postpositive) positive and confident about the truth of something; convinced

   I am certain that he wrote a book

2. (usually postpositive) definitely known

   it is certain that they were on the bus

3. (usually postpositive) sure; bound; destined

   he was certain to fail

4. decided or settled upon; fixed

   the date is already certain for the invasion

5. unfailing; reliable

   his judgment is certain

6. moderate or minimum

   to a certain extent

7. to ensure (that one will get something); confirm

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adverb

1. definitely; without a doubt

   he will win for certain

determiner

1. 1. known but not specified or named

      certain people may doubt this

   2. ( as pronoun; functioning as plural )

      certain of the members have not paid their subscriptions

2. named but not known

   he had written to a certain Mrs Smith

certain More Idioms  

1. see for certain.

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Usage

What are other ways to say certain? Someone who is certain of something is free from doubt or reservation about it. How is certain different from sure, confident, and positive? Find out on Thesaurus.com.

Etymology

Origin of certain

First recorded in 1250–1300; Middle English, from Old French, from Vulgar Latin certānus (unrecorded), from Latin cert(us) “sure, settled” (adjective use of past participle of cernere “to decide, separate, sift”) + -ānus -an

Example Sentences

What’s less certain is how individual software companies will benefit from the continuing AI boom.

From Barron's

Such tariffs are already in place on commodities such as steel and lumber and on certain industries such as makers of medium- and heavy-duty trucks.

From The Wall Street Journal

The outcome of Tuesday's vote is not certain.

From BBC

Stripping out certain one-time items, the company posted a loss of 16 cents a share.

From The Wall Street Journal

To this day, Karen says she is "triggered" by the sound of a key in a lock and the smell of a certain aftershave.

From BBC

Related Words

• absolute
• clear
• definite
• genuine
• positive
• real
• safe
• sure
• true
• undeniable