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
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?
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