OP: Of course, sure no problem, I've always seen it used as a gender neutral term.
Response to where the thread seems to be going:
Wow words are fascinating. As stated before, Otaku has a negative connotation in Japan.
Hayao Miyazaki complained the anime industry was full of Otaku [http://www.escapistmagazine.com/news/view/131872-Hayao-Miyazaki-Anime-Suffers-Because-the-Industry-is-Full-of-Otaku] and that is why the quality of anime is suffering.
The term "otaku" has a rather negative connotation in Japan and is used more to classify fans who obsess over something (this need not be anime). Miyazaki's specific concerns are over the lack of attention paid to people in real life. He said people in the industry "don't spend time watching real people" and can be characterized as "humans who can't stand looking at other humans." He then called the industry "full of otaku."
So I read this as he's basically saying these "otaku" are so afraid/disgusted by real humans that they check out from reality and prefer to live completely in their own fantasy worlds. That's pretty damn insulting.
Anyway, this is how I understand some of these words (English usage, I can't speak at all for the Japanese usage).
Anime: Animation specifically from Japan[footnote]though there's debate of whether animation made elsewhere but copies the style of anime (such as Avatar) is still considered anime[/footnote]
Otaku: A big fan of anime, may branch to Japanese video games and other Japanese things in general.
Fujoshi: A big (female) fan of yaoi
Weeaboo: (negative) someone so obsessed with Japan that they literally want to be Japanese.
Geek: (umbrella term) A big fan of something.
Nerd: A very smart person who traditionally wore glasses and knew how to use a computer well, definition is changing, now means basically the same as geek but may still be used toward somebody who knows a lot about tech.
Neckbeard: (Negative) (Male) replaced geek because geeks are cool now, carries other negative connotations, but I can't say specifically what they are.
Basement Dweller (negative) Gender neutral replacement for geek.