Sabbatarian /(?)/

Sab·ba·ta·ri·an

Sabbatarian

n.
  1. One who regards and keeps the seventh day of the week as holy, agreeably to the letter of the fourth commandment in the Decalogue.
  2. A strict observer of the Sabbath.

Sabbatarian

a.
  1. Of or pertaining to the Sabbath, or the tenets of Sabbatarians.