Source : Webster's Revised Unabridged Dictionary (1913)

Dunker \Dun"ker\, n. [G. tunken to dip.]
   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}.

   Note: The denomination was founded in Germany in 1708, but
         after a few years the members emigrated to the United
         States.

   {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.

Source : WordNet®

dunker
     n 1: an eater who dips food into a liquid before eating it; "he
          was a dunker--he couldn't eat a doughnut without a cup
          of coffee to dunk it in"
     2: a basketball player who is able to make dunk shots
     3: an adherent of Baptistic doctrines (who practice baptism by
        immersion) [syn: {Dunkard}, {Tunker}]