A black person is:
A person who is of African-American descent.
A black person is NOT:
Someone who is lacking in manners, steals things, or is less than intelligent.
Black people do not have black skin. Some do not even have dark skin. As long as a person is of African-American descent (such as half British, half African-American), he or she is black.
I am black, and I do not cheat, steal or use the phrase "What up, dog?" unless I am talking to an actual dog.
Black people are generally nice (at least, the ones I know are).