You know that girl in your school with a GPA over 100? She is a savant in the making. A savant is someone over-the-top smart, a scholar. It might take a savant only five minutes to do an entire math test.
Savant is the French word for "learned" and it goes back to the Latin word "to be wise", sapere. In English, a savant can be someone is who is wise and learned in general, or someone who is extremely skilled in a particular area, like your little brother who can rattle off the first three hundred digits of pi.