Someone who wastes vast amounts of time explaining the subtle (and irrelevant) differences between dork, geek, nerd, and anything else they have been labeled so they can feel slightly better about themselves.
While driving to the airport today with my 70 year old uncle, he made me aware that back in his day, dork meant penis, but has since beenreplaced by the word dick.
So if some super old guy calls you a dork, its not as harmless of an insult as you think.