a-geek.com

According to oxforddictionaries.com:

Pronunciation:/giːk/
noun
informal

* an unfashionable or socially inept person
* [usually with modifier] a knowledgeable and obsessive enthusiast:a computer geek

Origin:
late 19th century: from the related English dialect word geck 'fool', of Germanic origin; related to Dutch gek 'mad, silly'