A Seth is a smart aleck who won't be controlled no matter what you do. This is what makes parenting hard. Seths love gummy candy, and will do ANYTHING to get his hands on a large amount.
A Seth could also be a jerk that wants to sell you drugs.
"Bruh, stop cheating! You never follow the rules of anything! You are such a Seth!
"Meth Seth?! I thought we got you arrested! Just stop asking us if we want to buy drugs! You are a real Seth!"