1. (

• certain ,
• sure

) having or feeling no doubt or uncertainty; confident and assured; "felt certain of success"; "was sure (or certain) she had seen it"; "was very sure in his beliefs"; "sure of her friends" ;

2. (

• certain ,
• sure

) exercising or taking care great enough to bring assurance; "be certain to disconnect the iron when you are through"; "be sure to lock the doors" ;

3. (

• certain ,
• sure ,

) certain to occur; destined or inevitable; "he was certain to fail"; "his fate is certain"; "In this life nothing is certain but death and taxes"- Benjamin Franklin; "he faced certain death"; "sudden but sure regret"; "he is sure to win" ;

4. (

• sure

) physically secure or dependable; "a sure footing"; "was on sure ground" ;

5. (

• certain ,
• sure

) reliable in operation or effect; "a quick and certain remedy"; "a sure way to distinguish the two"; "wood dust is a sure sign of termites" ;

6. (

• sure ,
• trusted

) (of persons) worthy of trust or confidence; "a sure (or trusted) friend" ;

7. (

• sure

) infallible or unfailing; "a sure (or true) sign of one's commitment" ;

8. (

• sure

) certain not to fail; "a sure hand on the throttle" ;

9. (

• indisputable ,
• sure ,

) impossible to doubt or dispute; "indisputable (or sure) proof" ;

1. (

• surely ,
• certainly ,
• sure ,
• for_sure ,
• for_certain ,
• sure_enough ,
• sure_as_shooting

) definitely or positively (`sure' is sometimes used informally for `surely'); "the results are surely encouraging"; "she certainly is a hard worker"; "it's going to be a good day for sure"; "they are coming, for certain"; "they thought he had been killed sure enough"; "he'll win sure as shooting"; "they sure smell good"; "sure he'll come" ;