"Fred" seems to be cycling's nearest equivalent to "nerd" or "dork." It also seems to have two opposite definitions, depending on whom you ask:

(1) A person wearing lots of colorful Lycra riding clothing, on an ultra-expensive bike, and loaded down with every sort of flashy accessory that money can buy, but with no appreciable riding skills;

or

(2) A person wearing street clothes (likes jeans and a tee shirt), riding an old bike, and seemingly ignorant of the niceties of cycling culture, but with the skills to overtake all those proud "roadies" with their expensive bikes and leave them in the dust.

Myself, I'm somewhere in the middle. I look like (2) but don't have the riding skills to back it up, so I guess you'd call me an aspiring Type 2 Fred.