1†(a) Philosophy. An advocate or adherent of an antimaterialistic theory of creation. Obsolete rare. (b) . An advocate or adherent of the pneumatic theory of physiology.
2An advocate or practitioner of pneumatic medicine or chemistry.
Late 17th century; earliest use found in Thomas Tenison (1636–1715), archbishop of Canterbury. From ancient Greek πνευματ-, πνεῦμα + -ist.