Outside of the legal context, Prejudicial refers to words that assign people to a racial, ethnic or any other stereotype. For example calling an Irish person a "Mick" is prejudicial. Unless you're a Mick, of course. Then it is funny.
a) Why is this prejudicial language? I am not convinced this is prejudicial language. It might be based on many years of accurate observation, in much the same way as referring to someone as honest,...
Do you mean the definition? If you do, :A single distinct meaningful element of speech or writing, used with others (or sometimes alone) to form a sentence and typically shown with a space on either...