Someone who is amoral is one that does not know the difference between that which is right and that which is wrong. More and more western society is becoming amoral, as morality is taught as something that is relative to the situation.
Amorality is not to be confused with immorality. A person that is immoral is choosing to do that which is wrong, knowing full well that it is wrong. In many ways amoral is more dangerous. A person who knows they are lost can turn to what is right, but a person who has lost their compass will have a hard time finding their way at all.