Going beyond the clearly marked limits of regular retardedness.
Strangly enough, only people without down syndrome or other mental handicaps seem to venture into this frightening territory of hardcore tardness.
term is derived from the adj. hardcore, which has been used to define a strain of more aggressive punk rock from 1978-98. However the term mutated to encompass other shitty genres of quasi-punk sounding bands. These bands are also labled as "tardcore" by bands who feel they don't fit under the hardcore lable. Especially since the scene is dominated by dick-wagging testosterone junkies who sneer at anything xenomorphic to them.
Behaviour, as well as music like such also classify as tard core. What a diverse term.
Bill: Dude, did you just eat the sandwich you put your pubes on for your little brother to eat?
Ted: Uh, maybe... wait... yeah!
Bill: You are so fucking tard core.