Fiercely and playfully -- often at the same time -- Mary Daly used words to challenge the basic precepts of the Catholic Church and Boston College, where she was on the faculty for more than 30 years.Dr. Daly emerged as a major voice in the burgeoning women's movement with her first book, "The Church and the Second Sex," published in 1968, and "Beyond God the Father: Toward a Philosophy of Women's Liberation," which appeared five years later. That accomplishment was viewed, then and now, as all the more significant because she wrote and taught at a Jesuit college."She was a great trained philosopher, theologian, and poet, and she used all of those tools to demolish patriarchy -- or any idea that domination is natural -- in its most defended place, which is religion," said Gloria Steinem.Dr. Daly, whose relationship with Boston College grew tempestuous as she insisted that only women could take her classes, died Sunday in Wachusett Manor nursing home in Gardner. She was 81 and her health had failed in the past few years, including recent paralysis due to a neurological condition.