A Family that is perceived(usually by someone from the neighborhood) as hermitical; weird; eccentric; dysfunctional; queer; bewildering; constantly causing embarrasment to itself, etc...
My neighbor is such an Addams family. We never see any of their member come out; never ever seen anybody go in. But the lights would be on when night falls. Their curtain's always pulled and doors never opened or even ajar.
Basically someone who is: full of shits; talks shit all the time; lies or brags alot; don't keep promises; nonsensical; big mouth; makes unreliable statements; wise crack; says lot of things that people are not interested in... etc.
Foreign friend: Hey who is the president of the USA?
Johnny: Ah he's a shitto.
Foreign friend: huh what do you mean?
Johnny: George W. Bush
Foreign friend: Oh i see... is he good?
Johnny: He's a shitto
Ben: Hey Jack! how ya doing today?
Jack: how ya doing today
Ben: I said how ya doing?
Jack: I said how ya doing
Ben: Must you repeat everything i say?
Jack: Must you repeat everything i say