Collins English-English Dictionary

sure [ʃυə]

1. 1. adj [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. 2. adj [foll by of] having no doubt, as of the occurrence of a future state or event

   sure of success

3. 3. adj always effective; unfailing

   a sure remedy

4. 4. adj reliable in indication or accuracy

   a sure criterion

5. 5. adj (of persons) worthy of trust or confidence

   a sure friend

6. 6. adj not open to doubt

   sure proof

7. 7. adj admitting of no vacillation or doubt

   he is very sure in his beliefs

8. 8. adj bound to be or occur; inevitable

   victory is sure

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

   she is sure to be there tonight

10. 10. adj physically secure or dependable

    a sure footing

11. 11. adj [obsolete] free from exposure to harm or danger

12. 12. adv [sentence substitute] [informal] willingly; yes

13. 13. adv [sentence modifier] [informal] [chiefly US and Canadian] without question; certainly

14. 14. adv [Etymology] C14: from Old French seur, from Latin securus secure