The term 'open-and-shut' is used to describe a situation that is easily understood and resolved. The crossword solutions for this term are 'CASE' (4 letters) and 'reseal' (6 letters). A CASE is a container or covering, usually made of hard material, that is used to protect something inside. Resealing is the act of closing a container or covering again after it has been opened. Together, these two words describe a situation that is easily understood and resolved, as the container can be opened and then closed again.