Def. 1) A terrible condition that affects most of the
people you will ever meet causing a penis to grow off of said person's forehead.
Def. 2) That kid in your science class that deliberately failed all his tests making him "
cool".
Def. 3) Your
Boss and most of your colleagues.
Doctor: Sir, I'm afraid you suffer from Dickhead Syndrome.
Your
Boss: Is it bad?
Doctor: It's the most severe case that I've ever seen. It is possibly fatal.