Smarty (noun)

1. A person who is excessively or affectedly clever, especially in a self-satisfied or impudent way.
2. A person who is arrogant and thinks they are clever or superior.

Origin:

likely a shortened form of the phrase "smart aleck".

Examples:

1. He was always acting like a smarty and showing off his knowledge.
2. She was always correcting people, what a smarty.
3. The smarty thought he knew everything.
4. The smarty was always trying to one-up his friends.
5. He was a smarty who always had a clever comeback.