The term 'not external' can be described by two crossword solutions: 'INNER' (5 letters) and 'INWARD' (6 letters). Both words refer to something that is located within a certain boundary or area, as opposed to something that is outside of it. INNER and INWARD are often used to describe the relationship between two things, such as the relationship between an individual and their emotions or thoughts. In this context, the term 'not external' implies that something is not located outside of the boundary or area in question.