Ascetical

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.
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.
(in the early christian church) a monk; hermit.
relating to , the doctrine that one can reach a high spiritual state through the practice of extreme self-denial or self-mortification.
rigorously abstinent; austere:
an ascetic existence.
exceedingly strict or severe in religious exercises or self-mortification.
historical examples

we received the blessing of the leader of the giri branch of the swami order-a thin, ascetical monk with eyes of smiling fire.
autobiography of a yogi paramhansa yogananda

have we indeed outstripped the warrior and p-ssed the ascetical saint?
a chesterton calendar g. k. chesterton

that northern “custody of the senses” which is not an ascetical exercise, but an inner illumination thrown upon them.
rome mildred anna rosalie tuker

the orthodox idea of fasting is first of all that of an ascetical effort.
great lent: a school of repentance alexander schmemann

noun
a person who practises great self-denial and austerities and abstains from worldly comforts and pleasures, esp for religious reasons
(in the early christian church) a monk
adjective
rigidly abstinent or abstemious; austere
of or relating to ascetics or asceticism
intensely rigorous in religious austerities
adj.

1640s, from greek asketikos “rigorously self-disciplined, laborious,” from asketes “monk, hermit,” earlier “one who practices an art or trade,” from askein “to exercise, train,” originally “to train for athletic compet-tion, practice gymnastics, exercise.”
n.

“one of the early christians who retired to the desert to live solitary lives of meditation and prayer,” 1670s, from ascetic (adj.).