If someone is supersmart, they are very, very clever and know a lot of things.
Being supersmart is a really good thing. People might look up to you if you are supersmart.
Examples:
My sister is supersmart and gets all A's in school.
He's so supersmart, he can solve any problem.
The supersmart girl finished her homework in no time.
The supersmart robot could do all the work by itself.
The supersmart scientist knew everything about space.
I wish I was supersmart like him.