In my opinion, simply believing or stating that a certain race is inferior or superior to another is fine and in some cases morally obligatory (when and if the evidence implies it and the context makes it relevant and not insulting). It is when it is used to insult that it becomes wrong.

Since it is quite an emotive word that people generally don't like to be associated with I think it's definition should be and stay at "Prejudice, discrimination, antagonism and/or contempt directed against someone of a certain race (so that said person feels it) based on the belief that it is inferior to another".