Austerity in Jainism is called tapas. It means voluntary discipline and self-control aimed at purifying the soul. It involves reducing or giving up comforts, controlling senses, and performing penances with a calm, detached mindset.

Key ideas:

• Renunciation of worldly comforts to lessen karmic bonds.
• Self-control of thoughts, speech, and actions (non-violence, truth, celibacy where applicable, etc.).
• Practices like fasting, standing or sitting in penance, and simple living are common forms of tapas.
• The purpose is to burn past karmas and aid spiritual progress, leading to right belief, knowledge, and conduct.

Notes:

• In Jainism, tapas is primarily about inner purification (bhava), not about outward show. It is expected to be practiced with right intention and compassion for all beings.
• There are no essential doctrinal differences about tapas between Digambaras and Shvetambaras in the basic idea, though there may be differences in specific practices or prescriptions in certain texts.

If you’d like, I can explain how tapas is described in specific Jain scriptures or give simple examples of tapas you can practice today.