term used to describe a computer geek rejected from his own group, therefore aloner. Tries to down on other people by calling them gay, while usually hiding his own sexual problems. The ultimate insult to any "normal" person.
person 1: man that mike, he keeps trying ot down on me
person 2:yeh, we all know he's a mcwillis, just ignore him
person 1: probaly worried about his sexuality. . .