The Great Hindu Sage referred to in the crossword solution is Maharishi, a title given to a great sage or saint in Hinduism. Maharishi is a Sanskrit term meaning 'great seer' and is often used to refer to a spiritual teacher or leader. The term is also used to refer to a person who has achieved a high level of spiritual enlightenment. Maharishi is believed to have been the founder of the Vedic tradition of Hinduism, which is one of the oldest and most influential religious traditions in India. He is also credited with introducing the practice of meditation to the world.