1. niebuhr(n = noun.person) reinhold niebuhr - United States Protestant theologian (1892-1971); Array
is a kind of theologian, theologiser, theologist, theologizer
2. niebuhr(n = noun.person) barthold george niebuhr - German historian noted for his critical approach to sources and for his history of Rome (1776-1831); Array
is a kind of historian, historiographer