To be defined a "fucktard", that person displays the not-so-favorable acts of stupidity (being a retard) and being an insensitive person (being a jerk or fuck). Usually fucktards are complete idiots who also act like jerks at the same time. to be called a "fucktard" is worse being called a "retard" or "fuck" alone.
Person 1: " My co-worker was being a fucktard again."
Person 2: "Really?! The hell did he do?"
Person 1: "He couldn't shut up bragging boning teenyboppers at work. And in FRONT of the manager."
Person 2: "Whoa! He IS a fucktard!"