A tardo is the evolution of a retard. when a retard gains the ability to function among normal people but is still considered retarded because of his or her awkwardness. Tardos are prone to crapping their pants in public and will most likely try to attack you if you make too much eye contact. The best way to deal with tardos is to keep away.
Steve: Holy Crap!!! did you see that new kid. I was checkin her out and then she just friggin jumped out of her chair and tried to attack me. What a tardo.
Jorge: You know what steve? I think she just crapped her pants.