Words to watch out for

This section explores words you may hear in or used to describe a particular anime:

Aho
Impolite way of saying complete idiot

Baka
Regular way of saying complete idiot. Beat your anime watching child round the head if they call you this or the former entry.

Bishojo
Beautiful young girls.
Example:
Love Hina, Negima, Loveless, Candy Boy

Bishonen
Pretty boys. They appear most often in the yaoi category
Examples:
Loveless, Zoku Natsume Yuujinchou

Chibi
Means small, but often used to denote cute loli-esque characters.
Examples:
Rizelmine, Happy Lesson

Ecchi
A little similar to overtly sexual hentai though generally more softcore, from what I've come to understand.
Added info from Blog commenter Niamh,
"Ecchi, as I understand it, was derived from the pronunciation of the letter "H" (being the first letter of the word 'Hentai"). It is often used as a synonym for Hentai, but indeed the material is of a softer nature, i.e. more naughty than sexual. Think of Barbara Windsor of the Carry on films from a western perspective ;)"
Carry on Tentacles.

Futunari: Anime girls who have that little bit extra. Transgendered to be more precise. Mostly found in hentai.
Examples:
Bible Black, Mnemosyne is the only one I can think of that comes close to this in mainstream.

Hentai or H: (Don't pretend you don't know this). Used in the West as a catch all phrase for anime with a high sexual content. Also used to describe a perverted person. Not mainstream.
Example:
Bible Black

Henshin:
Transformation. Characters turn into superheroes. Think superman and Clark Kent. This word doesn't mean anything especially bad but anime that includes this often has slightly ecchi leanings. Dirty Pair, Puni Puni Poemy and Kekko Kamen all have these transformation scenes which generally involves the character dropping all their clothes, before suddenly being robed in some scantily clad superhero outfit (or never putting their clothes back on in the case of Kekko Kamen) and even growing larger breasts and curves. Sailor Moon (dubbed version) and Card Captor Sakura are a bit more innocent when it comes to this transformation scene.

Kawaii
Means 'cute'. Does not necessarily mean anything perverted, and can be used to describe adults as well as children, toys as well as people.

Guro or ero-guro: Meaning the 'erotic grotesque', these animes are not especially common but feature the most extreme images. Sexual torture, scat and dismemberment are quite common. This is mostly found in hentai and manga rather than mainstream anime but it does creep in occasionally.
Example:
Legend of the Overfiend and Mnemosyne includes some guro elements.

Loli/lolicon: Under-aged characters and those who desire them respectively. Pedophilia is often shown with a humorous bent in anime in a way that is deemed unacceptable in the west. Laws regarding Loli hentai are currently being reconsidered in Japan, with the possibility of banning them. I am not entirely sure of its legal status in Western countries.
Example:
Rizelmine, Doujin Work and Dokuro-chan (All non hentai)

Manga
Japanese comics. Where almost all anime is born.

Moe
Whilst basically meaning 'cute', Moe (according to Wikipedia) means 'budding', so can be used to denote cute school girls, but it does not necessarily refer just to younger characters. Considered a slightly more otaku term.
Examples:
Card Captor Sakura, Negima

Nekomimi
Cat girl. Basically girls (or boys) who have cat ears on their heads. Can sometimes have a tail, whiskers and paws but not necessarily. Odd fetish in Japan
Examples:
Loveless, Soul Eater

Nose bleeds
Not a keyword exactly but worth a mention. A nose bleed in anime is a comedy device which denotes sexual desire and frustration. So, say a boy accidentally walks in on a girl changing and he's likely to have a sudden trickle of blood from his nose. I really have no where this phenomenon came from.

Otaku
Obsessive anime and manga fan. Considered very derogatory in Japan, taken to be some kind of status symbol in the West. Think of a comic book geek who sleeps with a cardboard cutout of catwoman and you're barely half way there.

Seinen
Anime directed at adult males: 18-30
Examples:
Monster, Genocyber, Welcome to the NHK

Shonen:
Boy. Also used to describe anime for the young male demographic. Naruto and Bleach were originally serialized as Manga in Shonen Jump, a popular boys magazine.
Examples:
Naruto, Bleach, One Piece

Shota/Shotacon:
Male loli's basically and the older women/men who love them respectively.
Example:
Loveless, Rizelmine, Negima

Shoujo:
Girl. Used also to denote anime aimed at girls (or creepy Western men)
Examples:
Card Captor Sakura, Loveless, Negima

Yaoi:
Boy on boy. Oddly enough, this genre is mostly for Japanese straight girls.
Example:
Fake, Loveless

Yuri:
Girl on girl. More often then not this is used for slapstick reasons in anime, with the high school crush being the most common situation that yuri appears.
Example:
Candy Boy, Bleach, Azumanga Diaoh