sure

American  

[shoor, shur] / ʃʊər, ʃɜr /

adjective

surer, surest

1. free from doubt as to the reliability, character, action, etc., of something.

   to be sure of one's data.

2. confident, as of something expected.

   sure of success.

3. convinced, fully persuaded, or positive.

   to be sure of a person's guilt.

4. assured or certain beyond question.

   a sure victory.

5. worthy of confidence; reliable; stable.

   a sure messenger.

6. unfailing; never disappointing expectations.

   a sure cure.

7. unerring; never missing, slipping, etc..

   a sure aim.

8. admitting of no doubt or question.

   sure proof.

9. destined; bound inevitably; certain.

   sure death.

10. Obsolete.  secure; safe.

11. be sure, to take care (to be or do as specified); be certain.

    Be sure to close the windows.

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adverb

1. Informal.  certainly; surely.

   It sure is cold out. Sure, I'll come.

idioms

1. for sure,  as a certainty; surely.

   It's going to be a good day, for sure.

2. make sure,  to be or become absolutely certain.

   I'm calling to make sure that you remember to come.

3. to be sure,

   1. without doubt; surely; certainly.

   2. admittedly.

      She sings well, to be sure, but she can't act.

4. sure enough,  as might have been supposed; actually; certainly.

   Sure enough, the picnic was rained out.

sure British  

/ ʃɔː, ʃʊə /

adjective

1. (sometimes foll by of) free from hesitancy or uncertainty (with regard to a belief, conviction, etc)

   we are sure of the accuracy of the data

   I am sure that he is lying

2. (foll by of) having no doubt, as of the occurrence of a future state or event

   sure of success

3. always effective; unfailing

   a sure remedy

4. reliable in indication or accuracy

   a sure criterion

5. (of persons) worthy of trust or confidence

   a sure friend

6. not open to doubt

   sure proof

7. admitting of no vacillation or doubt

   he is very sure in his beliefs

8. bound to be or occur; inevitable

   victory is sure

9. (postpositive) bound inevitably (to be or do something); certain

   she is sure to be there tonight

10. physically secure or dependable

    a sure footing

11. obsolete  free from exposure to harm or danger

12. (usually imperative or dependent imperative; takes a clause as object or an infinitive, sometimes with to replaced by and) to be careful or certain

    be sure and shut the door

    I told him to be sure to shut the door

13. without a doubt; surely

14. 1. (takes a clause as object) to make certain; ensure

    2. (foll by of) to establish or confirm power or possession (over)

15. informal  as might have been confidently expected; definitely: often used as a sentence substitute

16. 1. without doubt; certainly

    2. it has to be acknowledged; admittedly

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adverb

1. informal  (sentence substitute) willingly; yes

2. informal  (sentence modifier) without question; certainly

sure More Idioms  

More idioms and phrases containing sure

• for certain (sure)
• make sure
• slow but sure
• to be sure

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Usage

What are other ways to say sure?

Someone who is sure of something is free from doubt about its reliability or character. How does sure compare to synonyms certain, confident, or positive? Learn more on Thesaurus.com. 

Commonly Confused

Both sure and surely are used as intensifying adverbs with the sense “undoubtedly, certainly.” In this use, sure is generally informal and occurs mainly in speech and written representations of speech: She sure dazzled the audience with her acceptance speech. It was sure hot enough in the auditorium. Surely is used in this sense in all varieties of speech and writing, even the most formal: The court ruled that the law was surely meant to apply to both profit-making and nonprofit organizations. See also quick, slow.

Other Word Forms

• oversure adjective
• oversurely adverb
• oversureness noun
• sureness noun
• unsure adjective
• unsurely adverb
• unsureness noun

Etymology

Origin of sure

First recorded in 1300–50; Middle English sur(e), from Middle French sur, Old French seur, from Latin sēcūrus “carefree”; secure

Example Sentences

“I’m not sure I want to do that.”

From Salon

To be sure, prediction markets can be poor at forecasting, as was shown with one Supreme Court pick years ago.

From MarketWatch

To be sure, prediction markets can be poor at forecasting, as was shown with one Supreme Court pick years ago.

From MarketWatch

As I’m sure you know, the cost of college is astronomical.

From MarketWatch

Millions of users love it, but they aren’t sure it will last.

From The Wall Street Journal

Related Words

• assured
• clear
• confident
• convinced
• positive