The second limb of yoga, used along with yama to codify the dos and don’ts of yoga.
If your intelligence rises to a certain height, you will not need any morality. Only when intelligence is lacking, you must tell people what not to do. If someone’s intelligence has risen, they need not be told what to do and what not to do. He did not utter one word as to what to do and what not to do. The yama and niyama of the Yogic system are Patanjali’s making, not that of Adiyogi. Patanjali came much later.