The term 'purely spiritual' can be described by two crossword solutions: 'PLATONIC' (8 letters) and 'Platonical' (10 letters). PLATONIC is derived from the ancient Greek philosopher Plato, who believed that the highest form of love was a spiritual bond between two people, rather than a physical one. Platonical is an adjective used to describe something that is related to or based on Plato's philosophy. Both words refer to a relationship that is purely spiritual in nature, without any physical or romantic attachment.