See also half-tard and quarter-tard. A full-tard is one who has 100% retard blood coarsing through their brains. This can mean two things. Half the time, the person will be born a retard, with limited brain capacity and other problems. The other half of the time, the person will slip through the nets of schooling and manage to finish some amount of their life with everyone thinking they are normal. However, eventually their blood will mature and they will begin acting like a retard. While they have adapated to society (see evolution) they still do not process the brain power to function without failure. They will constantly do stupid things.
Guy 1: "Look at Gillis making that pizza. He's actually having trouble."
Guy 2: "Dude, Gillis is a fucking full-tard. He can't help it."
Guy 1: "Ah. Fucker."