I dont know what this word means.

Weeabo is intended to be a derogatory insult, along with Wapanese. Incidentally, "Otaku" is considered an insult in Japan. They think it's weird that foreign ファン are proud to call themselves as such.

A nicer way to think of it is that anyone who calls あなた a Weeabo is xenophobic as hell & resents あなた for not thinking their preferred culture is superior in every way.

It's primarily aimed at shameless obsessive otaku, especially the noobs who have only been into アニメ for about 5 years. But much like how Hipster has ロスト all meaning & has no definitive definition, it's also used によって アニメ haters to describe anyone who likes anime.

Also used within the fandom, aimed at passionate noobs, used によって older ファン who've long settled into the fandom like a marriage where あなた stay because it's familiar, but the romance is gone. The noobs remind them of how embarrassing they themselves once were.

Anyway, Weeabo characteristics are the following:
*Bringing アニメ & マンガ into any conversation it has no business being.
*Wearing cosplay outside of a convention.
*Proudly displaying your poorly drawn shipping fanart on the internet.
*Being able to name all the Pokemons AND not hating the Final ファンタジー franchise.
*Constantly reminding people that English 音楽 sucks & American musicians are unattractive (still guilty as shit of this on my part).
*Being a proud & open ファン of yuri, yaoi, shotacon, lolicon, sibling complex, または furries. (Guilty of some of this too, but America needs to get over it's damn homophobia already).
*Using Japanese words in conversations with non アニメ fans. (Incidently, this also irritates the shit out of seasoned アニメ veterans).
*Getting extremely defensive when another otaku points out that your're mispronouncing a word または using it incorrectly.
*Having a ship-to-ship combat in public.
Getting toxic when もっと見る well-behaved otaku tell あなた that your embarrassing yourself as well as them.
*Owning an obscene amount of UFO cather ドール & NECA figurines.
*Owning a マウス pad with a boob armrest & a body 枕 with a naked アニメ character on it.
*Having hentai, wallscrolls, & マンガ posters on your walls instead of pinups of real people.
*If being a ファン of アニメ is literally your only defining characteristic at school, then Weeabo is actually a well-deserved タイトル used to label a one-character.

From what I've heard, a weeaboo is a person that says they know everything about anime/is an アニメ fan, but actually doesn't. あなた probably aren't a weeaboo, though. If あなた don't want to seem like one, refrain from over using words like "kawaii" "desu", etc.

Basically it means someone who likes アニメ A LOT to the point where they put 日本 on a high pedestal and think it's the best place on earth and it's only アニメ and they generally put down America/other countries to make 日本 look better and they force アニメ onto other people and can't understand why a person doesn't 愛 it. It's really not a nice thing to call someone, and there's a lot of negative traits associated with it including forcing (usually yaoi) parings on people, harassing Asians (because they think they're all Japanese) really bad cosplay in inappropriate places, speaking in broken Japanese pretending to know the language (desu, sugoi, kawaii,and neko are usually some favorites), and drawing bad fanart/fanfictions and forcing people to look at it thinking they're the best and that they have no need for improvement, the 一覧 goes on, if あなた want here's a funny tumblr all about people's encounters with them.

link

When you're friend 発言しました you're a weeaboo for Len they probably meant that you're super obsessed, think he's the best singer ever etc. Now I don't know あなた または them または how they 発言しました it so they may have just been joking, but Weeaboo is usually meant as an insult.