as·cet·ic 
(ə-sĕtĭk)
(ə-sĕtĭk)n.
A person who renounces material comforts and leads a life of austere self-discipline, especially as an act of religious devotion.
adj.
Relating to, characteristic of, or leading a life of self-discipline and self-denial, especially for spiritual improvement. See Synonyms at severe.
[Late Greek askētikos, from Greek askētēs, practitioner, hermit, monk, from askein, to work.]
as·ceti·cal·ly adv.