Aparigraha is the concept of non-possessiveness or non-greediness. It is both a Jain concept and a part of the Raja Yoga or Ashtanga Yoga traditions. The term usually entails the limitation of possessions to what is necessary or important, which changes with the time period, though sadhus would not have any possessions.
In the Yoga Sūtras (II, 30), a basis of the Raja Yoga tradition, it is listed as the fifth Yama or code of self-restraint, after with Ahimsa (nonviolence), Satya (truthfulness), Asteya (not stealing), and Brahmacharya (celibacy). In the Haṭha Yoga Pradīpikā (I, 17), kṣhamā dhṝtiḥ is listed as the fifth yama; the four others, ahiṃsā satyamasteyaṃ brahmacharyaṃ, being the same.
Aparigraha is the Sanksrit word for greedlessness or non-grasping. It comes from the word parigraha, which means reaching out for something and claiming it for oneself; by adding the 'A' it becomes the antonym. Aparigraha, unlike Asteya, means taking what is truly necessary and no more. This concept also holds true when applying for gifts which are not to be accepted.