In Taoism; a xian is used to describe an enlightened person; almost always immortals. They have; through self-reflection and devotion; reached a state in Taoism where they have attained spiritual and physical immortality; usually also involving methods such as alchemy; breath meditation; qigong and tai chi.

Xian are often described as superhuman and with a variety of magical and supernatural abilities; such as immunity to heat and cold; flight; and superhuman speeds. Some can survive on just air and dew; or can use their magic to bring death or grant life.