Source : Webster's Revised Unabridged Dictionary (1913)

Quietist \Qui"et*ist\, n. [Cf. F. qui['e]tiste.] (Eccl. Hist.)
   One of a sect of mystics originated in the seventeenth
   century by Molinos, a Spanish priest living in Rome. See
   {Quietism}.

Source : WordNet®

quietist
     n : a religious mystic who follows quietism