ascetic

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A person who renounces material comforts and leads a life of austere self-discipline, especially as an act of religious devotion.
2. adj. Leading a life of self-discipline and self-denial, especially for spiritual improvement. See Synonyms at severe.
3. adj. Pertaining to or characteristic of an ascetic; self-denying and austere: an ascetic existence.

Century Dictionary and Cyclopedia

1. Practising special acts of self-denial as a religious exercise; seeking holiness through self-mortification; hence, rigidly abstinent and self-restrained as to appetites and passions.
2. Hence Unduly strict or rigid in religious exercises or mortifications; severe; austere.
3. Pertaining to or resembling the ascetics.
4. n. In the early Christian church, one who practised unusual self-denial and devotion; in modern usage, also one who retires from the customary business of life and engages in pious exercises; a hermit; a recluse.
5. n. plural [capitalized] The title of certam books on devout exercises: as, the Ascetics of St. Basil.

Wiktionary

1. adj. Of or relating to ascetics; characterized by rigorous self-denial or self-discipline; austere; abstinent; involving a withholding of physical pleasure.
2. n. One who is devoted to the practice of self-denial, either through seclusion or stringent abstinence.

GNU Webster's 1913

1. adj. Extremely rigid in self-denial and devotions; austere; severe.
2. n. In the early church, one who devoted himself to a solitary and contemplative life, characterized by devotion, extreme self-denial, and self-mortification; a hermit; a recluse; hence, one who practices extreme rigor and self-denial in religious things.

WordNet 3.0

1. adj. pertaining to or characteristic of an ascetic or the practice of rigorous self-discipline
2. n. someone who practices self denial as a spiritual discipline
3. adj. practicing great self-denial