Mother Teresa, for one, was a Roman Catholic NUN who dedicated her life to helping the poor and sick. She was born in 1910 in what is now Macedonia and joined the Sisters of Loreto at the age of 18. She founded the Missionaries of Charity in 1950 and received the Nobel Peace Prize in 1979 for her humanitarian work. Her selfless service earned her the title of 'Saint of the Gutters' and she is remembered as an icon of compassion and charity. The three letter crossword solution for Mother Teresa, for one, is NUN.