To dream that you are hiding suggests that you are keeping some secret or withholding some information. You may not be facing up to a situation or dealing with some issue. However, you may be getting ready to reveal something and confess before somebody finds out. In particular, to dream that you are hiding from some authority figure (police, parent, teacher…) implies feelings of guilt.
To dream that someone is hiding indicates that you are looking for a sense of security and protection.