Pronoun. - Derogatory slur used for black people.
Not prevalent worldwide but was commonly used in 1970's New Zealand.
"Damn Mitters stole my bike."
A mitter is a fan of a (usually badly) dubbed anime, that refuses to learn anything about the original show, or about the diffrences between the two.
Person 1: I love One Piece! Zolo rocks!
Person 2: Y'know, he was supposed to be called Zoro originally and loads of stuff was edited out of the dubbed version of One Piece.
Person1: Don't tell me about that stupid Japanese version, why watch something in a language you don't understand! The dub is fine - I bet it's even better than the stupid Japanese version!
Person 2: Gawd, you're such a mitter!