The term 'Just Not Done' can be broken down into four crossword solutions: TABOO (5 letters), RAW (3 letters), IMPROPER (8 letters), and Highly Irregular (15 letters). TABOO refers to something that is forbidden or not allowed, while RAW suggests something that is uncooked or unprocessed. IMPROPER implies something that is not suitable or correct, and Highly Irregular indicates something that is far from normal or standard. Together, these words suggest that a certain action or behavior is not acceptable and should not be done.