Dork is a term used to describe someone who has unusual interests and is, at times, silly or stupid. A dork can also refer to someone who acts on his own motives without caring about his peers' opinions. The term occasionally implies stupidity, though perhaps less often than it once did, and it can paradoxically imply an unadmirable (bookish, academic) intelligence, much like the terms "nerd" and "geek."
It is popularly asserted that the term originated as whalers' occupational slang for the penis of a whale (oosik), and by transfer became an anatomical insult, undergoing subsequent generalization and amelioration to its present meaning. One of the earliest documented uses of the word "dork" is a 1961 publication (referencing 1953), in which the meaning is clearly penis in reference with the whales<1>. In its current most common usage, however, the phallic association is ignored and the term is not considered particularly vulgar.The adjectival form of dork is dorky, a word that was mainstream enough by 1971 to appear in a Peanuts comic strip.<2>
http://en.wikipedia.org/wiki/Dork