Name-calling is much less serious than hate speech. It is not illegal unless the "name" implies a crime, e.g. "murderer", "thief", "fraud". If that name implying a crime is applied to an entire group, it may be hate speech - else it is one form of criminal libel.
More common is civil libel which is just ordinary damage to repute that costs someone something in the marketplace. This does not usually involve names with legal definitions though it might imply wrongdoing, e.g. calling someone a "con artist".