Sadhu, also spelled saddhu, is a religious ascetic, mendicant or any holy person in Hinduism and Jainism who has renounced the worldly life. They are sometimes alternatively referred to as yogi, sannyasi or vairagi.
Sādhu means one who practises a 'sadhana' or keenly follows a path of spiritual discipline. Although the vast majority of sādhus are yogīs, not all yogīs are sādhus. From Wikipedia
