Dunker

prop. n.
  1. One of a religious denomination whose tenets and practices are mainly those of the Baptists, but partly those of the Quakers; -- called also Tunkers, Dunkards, Dippers, and, by themselves, Brethren, and German Baptists, and they call their denomination the Church of the Brethren.
    2. Seventh-day Dunkers ,
    a sect which separated from the Dunkers and formed a community, in 1728. They keep the seventh day or Saturday as the Sabbath.