Definition - What does Master mean?
Master, in the context of yoga, is generally used to refer to a person who has achieved a level of self-mastery. A master may be considered as a yogi who is Self-realized. The title may also be used by a yoga student as a respectful way to address their guru or spiritual leader. In fact, guru is a Sanskrit term meaning “master” or “teacher.”
It is said in the Bhagavad Gita that it is possible to acquire transcendental knowledge from a master through humble service, reverence and devotion to them. The master may have the power to enlighten the minds of his/her students, to give them initiatory mantras, and/or to instruct them in rituals and ceremonies for their spiritual development.
Yogapedia explains Master
Some teachings state that the measure of whether someone is a master is their ability to enter at will into a state where they cease to breathe, known as savikalpa samadhi. They will also have attained immutable bliss, or nirvikalpa samadhi. This is a spiritual measure as opposed to a physical or intellectual one.
Devotion to the master may be considered a form of yoga in itself, known as Master yoga, which is a type of Bhakti yoga. For those following this path, daily connection to an enlightened master may take the form of prayer or asking for guidance and help. This connection may help the yogi hear the voice of their own inner wisdom, which is the same as that of the enlightened master.
Other yogis warn of the dangers of unquestioningly following a self-proclaimed yoga “master.” They advise, instead, that students of yoga take responsibility for their own actions and behavior and maintain their critical thinking.