the GNU version of the Collaborative International Dictionary of English
n. One of a class of religious reformers in Germany in the 17th century who sought to revive declining piety in the Protestant churches; -- often applied as a term of reproach to those who make a display of religious feeling. Also used adjectively.
The Century Dictionary and Cyclopedia
n. One of a class of religious reformers in Germany in the seventeenth and eighteenth centuries.
Word Usage
"Dr Ganiel said "pietist" evangelicals - those who had decided that the world of politics was simply too grubby for Christians to take part in - could be reinforced by Mrs Robinson's demise."