One who lives in seclusion, often for religious meditation.
Note: The adjective form is either recluse or reclusive.
Henry David Thoreau and Charles Darwin form both a spectacular comparison and contrast. Both Thoreau and Darwin were voyagers. One confined himself to the ever widening ripples on a pond until they embraced infinity. The other went around the world and remained for the rest of his life a meditative recluse in an old Victorian house in the English countryside. . . . Both men were insatiable readers, and composers of works not completely published in their individual lifetimes. Both achieved a passionate satisfaction out of their association with wilderness. Each in his individual way has profoundly influenced the lives of generations that followed him.
—Loren Eiseley The Unexpected Universe (1969)