For lack of a better short answer: A closet Geek.

A Non-Associative Geek (NAG) is one who looks like a geek and carries himself like a geek, but he doesn't participate in geek society. Perhaps they dabble a little bit in perl, maybe they have a linux box, maybe they know HTML, C++ and computer hardware. But the difference is that the person's main goal in life has nothing to do with either of these. The NAG may not go to conventions. The NAG may not want to talk about such things all the time. The NAG may be far more interested in other things.

For example, I am a Landscape Architect. I am also a musician. I am a geek, of sorts, but that isn't my priority (actively or passively). Therefore, i'm a NAG.