If you say that a leopard does not change its spots or a leopard cannot change its spots, you mean that it is not possible for someone bad or unpleasant to change and become good and pleasant. A liar is a liar, and a leopard cannot change its spots. Note: This expression is often varied. This racist leopard has in no way changed his spots. I believe a leopard can change his spots, and this guy is really committed. Note: A form of this proverb is used in the Bible, by the prophet Jeremiah, to say that wicked people never change: `Can the Ethiopian change his skin, or the leopard his spots? Then may ye also do good, that are accustomed to do evil.' (Jeremiah 13:23)