Ascetic

Part of speech: noun (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. I am far from commending those ascetics that take up their quarters in deserts. Norris. Ascetic theology, the science which treats of the practice of the theological and moral virtues, and the counsels of perfection. Am. Cyc.

Part of speech: adjective (a.)

Extremely rigid in self-denial and devotions; austere; severe. The stern ascetic rigor of the Temple discipline. Sir W. Scott.