a person who dedicates his or her life to a pursuit of contemplative ideals and practices extreme self-denial or self-mortification for religious reasons.
2.
a person who leads an austerely simple life, especially one who abstains from the normal pleasures of life or denies himself or herself material satisfaction.
1640s, from Gk. asketikos "rigorously self-disciplined," from asketes "monk, hermit," from askein "to exercise, train," originally "to train for athletic competition, practice gymnastics, exercise." The noun meaning "one of the early Christians who retired to the desert to live solitary lives of meditation