Fucktard - n.
1. A fucking retard. usually someone lacking in intelligence and/or personality.
usage - "You are such a fucktard sometimes!"
2. A person who has sexual intercourse with a mentally challenged person.
3. A mentally challenged person with whom sexual intercourse is had.
4. You are probably one of the above. Add up all the mentally challenged persons with whom you have had sex to find out which. If you can't count that high, you are the tard.