Mahatma is a title of great respect in India for a person people see as very wise and very good — almost holy. It is not a job, and it is not a name you are born with; other people give it to you. The most famous Mahatma in the world is Gandhi, so many students meet the word first in history class as if it were his first name. It is not. His name was Mohandas; Mahatma was the honour placed in front of it, like saying “great soul.” You will almost never hear it used for a living person in ordinary English now, except when people talk about Gandhi or, more rarely, other Indian holy figures of the past. It feels formal and a little old, and outside writing about India it is uncommon.