Translation

otaku / geek / nerd / fan

Meaning

A person with an obsessive interest in a particular hobby, especially anime, manga, video games, or idols. While originally a Japanese term that sometimes carried negative connotations of being socially awkward, it has been widely adopted in English to describe passionate fans, often with a more positive or neutral nuance.

Examples

• He's a huge anime otaku; he knows everything about every series.
  彼は大のアニメオタクで、あらゆるシリーズについて何でも知っています。
• The convention was full of otaku dressed as their favorite characters.
  そのコンベンションは、お気に入りのキャラクターに扮したオタクでいっぱいでした。