An ascetic is one who practices a renunciation of worldly pursuits to achieve spiritual attainment.

Lao Zi, Gautama Buddha, Mahavir Swami and Jesus can all be considered ascetics. These people left their families, possessions, and homes, and in the eyes of their followers demonstrated great spiritual attainment.

Monks, yogis, hermits and—in some religions—priests also lead ascetic lives.

Asceticism in Buddhism

Ascetic practice comes straight from the Vinaya Pitaka of the Tripitaka, monastic body of rules taught by Gautama Buddha, his way of life. As a form of moderation, the Buddhist monasticism has a reputation for living in austerity compared to western standards.

This order is known as the Sangha, the community of monastics. In the Theravada school, prevalent in Myanmar, Sri Lanka, and Thailand, monks eat one vegetarian meal a day and fast until sunrise. Between midday and the next meal the following day, a strict life of celibacy, scripture study, chanting, meditation and occasional cleaning forms most of the duties. These practices must be conducted in a state of mindfulness and concentration, here and now, to benefit from the experience. Called the Patimokkha, 227 monastic rules govern a monk or Bhikkhu in Pali, and 311 for the Bhikkhuni nun. In Mahayana, although the rules have been lessened, monastics stress more on meditation than doctrine and insist on intuitive insight.

Asceticism in Eastern Christianity

Asceticism is the set of disciplines practiced to work out the believer's salvation, and further the believer's repentance. Although monks and nuns are known for especially strict acts of asceticism, some asceticism is expected of every believer, for the good of that believer. Ultimately, it is believed, salvation comes only by the grace of God, but God's grace and right belief are expected to produce changes in behaviour. Changes in behaviour can also influence beliefs. Asceticism can include anything from taking part in prayers with the church, fasting, almsgiving, or even working hard not to lose one's temper or similar acts of restraint and self-control. Corporate prayers are generally prayed as a "liturgy", which literally means a "work of the people."