Mahatma (Mə-HÄT-mə) is Sanskrit for "Great Soul" (mahātmā: mahā (great) or ātman [soul]). It is similar in usage to the modern Christian term saint. This epithet is commonly applied to prominent people like Mohandas Karamchand Gandhi, Munshiram (later Swami Shraddhananda), Lalon Shah and Jyotirao Phule. According to some authors Rabindranath Tagore is said to have used on March 6, 1915, this title for Gandhi;. Some claim that he was term Mahatma by the residents of Gurukul Kangadi in April 1915, and he in turn termed the founder Munshiram a Mahatma (who later became Swami Shraddhananda). However a document honoring him on Jan 21, 1915, at Jetpur, Gujarat, termed him Mahatma is preserved. The use of the term Mahatma in Jainism to denote a class of lay priests, has been noted since the 17th century.
Example via www.ramdass.org: Mahatma Gandhi