Permission to depart is a term used to describe the process of being granted permission to LEAVE a certain place or situation. It is often used in the context of military personnel who are given permission to LEAVE their post or a school setting where students are given permission to LEAVE the premises. The term can also be used in other contexts, such as when someone is given permission to LEAVE a job or a country. The crossword solution for this term is 'LEAVE, ' which is a five-letter word.