A harmonious relationship is one in which two or more people have a strong connection and understanding of each other. This type of relationship is often characterized by mutual respect, trust, and understanding. The crossword solutions for the term 'harmonious relationship' are 'RAPPORT, ' 'sync, ' and 'synch.' These words all refer to a relationship that is in harmony and balance. RAPPORT is a close and harmonious relationship in which the people involved understand each other's feelings or ideas and communicate well. Sync and synch both refer to the synchronization of two or more things, such as thoughts, actions, or feelings, in order to create a harmonious relationship.