In Buddhism, it is used of one who has achieved tranquillity (santi; cf. ŚANTI) as a result of emancipating himself from views (see DIṬṬHI) and passions (rāgā) and who therefore advocates the doctrine of tranquillity (santivāda—Sutta Nipāta 5. 845). In later canonical and post-canonical Buddhist literature the word is used to mean one who practises restraint in the triple activity of thought, word, and deed. In Jainism, it has become the common word to denote the avowed ascetic.
"Muni." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (September 23, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/muni
"Muni." The Concise Oxford Dictionary of World Religions. . Retrieved September 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/muni