certain

[ sur-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.

pronoun

1. certain ones:

   Certain of the members declined the invitation.

certain

/ 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. make certain of
   to ensure (that one will get something); confirm

adverb

1. for certain
   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

Word History and Origins

Origin of certain¹

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

Word History and Origins

Origin of certain¹

C13: from Old French, from Latin certus sure, fixed, from cernere to discern, decide

Idioms and Phrases

Idioms

1. for certain, without a doubt; surely:

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

More idioms and phrases containing certain

see for certain .

Example Sentences

While X’s privacy policy says that the company will not sell user data to third parties, it does share some information with certain business partners.

From Los Angeles Times

While some tariffs have been in existence long before Trump's presidency, the U.S. enacted new tariffs during his first administration, such as the Section 301 tariffs that added taxes on certain imported goods from China.

From Salon

Newman argued there still needed to be "clarity" about whether the civil service knew of certain donations before appointing Sargeant, Middleton and Corfield.

From BBC

In order to do so, developers would need to include a certain percentage of affordable units — and the property must be near transit or along a major street near jobs and good schools.

From Los Angeles Times

He said while murder and causing or allowing the death of a child were the charges on the indictment, manslaughter could also be considered if the jury was not certain that murder had been proved.

From BBC

Related Words

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

When To Use

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.