Masquerade

To dream that you are at a masquerade ball, denotes that your indulgence in sinful and foolish pleasures will lead to the neglect of your business and domestic duties. It also symbolizes deceit. If everyone was in costume except you, this is a warning against false friends.

To dream that you are wearing a costume, indicates that you are putting on a false face toward others. You are not being honest with people around you.