A person who is incapable of doing anything, be it singing fighting or looking good. Stupid and cant be of any use to anyone or anything. The worst thing to be used as a insult.people who are often useless think they are the best at everything when they're not.
Jack: I'm scared to think, can you decide things for me.
Gas Sation Attendant(GSA): Didn't you just graduate from college?
Jack: Yes I have a college duh-gree.
GSA: Ah, I see. Ok. You gave me $20...
Jack: Yeah, thats a twenty dollar bill, right?
GSA: ...and you put $16.50 on pump 11.
Jack: Stop. Just give me my change.