Weeaboo
"Ohio /tg/-kun, you are looking kawaii today uguu~ (ﾉ◕ヮ◕)ﾉ*:･ﾟ✧. Shall we play pretend on the futon after we eat our bento boxes desu? (>^3^)> Don't be Tsundere, you baka! It'll be sugoi! " - Sample text of a typical weeaboo
Weeaboo is a noun/adjective derived from a Perry Bible Fellowship comic, reaching internet stardom after the term was used as a wordfilter for "wapanese" on /b/. Although used in the comic as a nonsense word, it has since become synonymous with "wapanese" (itself short for "wannabe Japanese") until it supplanted the original term altogether. The term typically refers to people who believe that Japanese stuff is better simply because it is Japanese, with implications of harboring an unhealthy obsession with the culture and media of Japan (such as anime) while simultaneously managing to know very little about it. The term has spun off to describe other types of obsessions, such as Teaboo (girls obsessed with stereotypical Proper British culture, specifically the new Sherlock show and The Eleventh Doctor), Koreaboos (girls obsessed with K-Pop boy bands; considering the West hasn't really had actual boy bands since the 90s, it's not hard to see why) and Wolfaboo (kids obsessed with wolves, may or may not overlap with furries).
They are also known to hate all other Asian cultures and think that Japan is the "Best Asia Country Ever!", despite not knowing that just seventy years ago (and before!), the Japanese and Japan itself was one of the most conservative, imperialistic, xenophobic, theocratic, fascist nations in the world, hated or despised by almost everybody else, with the majority of the vote stemming from China and Korea (just open a history book you lazies). Modern Japan was given a rise in popularity due to American propaganda, as THE Capitalist Ally in the East, and the new Japanese generation, after being nuked to submission, putting on a new liberal democratic theme presenting themselves as sexually-liberal free-market libertarians with almost no similarity to their past conservative-fascist ancestors, to the point that they became the opposite. While conservative-Imperial Japan boasted a high population rise, modern anime Japan is almost sterile to the point of extinction. This isn't surprising, given their issues with having space for everyone (fortunately, not as bad as it could be... yet). It helps that conservative-Imperial Japan arranged-married pretty much everyone. It was much quicker to get people making babies that way.
In Japan, the Japanese have a similar concept they call the "Otaku"; there, an Otaku is basically a shut-in super-nerd who never leaves their room and obsesses over a typically nerdy hobby, usually anime/manga, and often leads to hoarding useless crap in their tiny apartment. Weeaboos appropriated the term to simply mean "anyone who watches anime / reads manga," so be wary about applying the term across cultural boundaries.
Fun fact: Japanese people see no real distinction between eastern and western animation. If you ask someone what their favorite anime is, they're as likely to reply "Spongebob Squarepants" as "Naruto." Weeaboos, on the other hand, are extremely adamant that there is a massive fucking difference between Japanese anime and all other forms of animation, and that any non-Japanese animation that mimicks anime isn't true anime (one such example is Avatar: The Last Airbender. Looks like anime, but made in America).