sabbatarian

noun

1. a person who observes the seventh day of the week, Saturday, as the Sabbath.
2. a person who adheres to or favors a strict observance of Sunday.

adjective

3. of or relating to the Sabbath and its observance.

noun

1. a person advocating the strict religious observance of Sunday
2. a person who observes Saturday as the Sabbath

adjective

3. of or relating to the Sabbath or its observance

n.1610s, “a Christian unusually strict about Sabbath observation,” from Latin Sabbatarius (adj.), from Sabbatum (see Sabbath). Meaning “member of a Christian sect which maintained the Sabbath should be observed on the seventh day” is attested from 1640s; earlier sabbatary (1590s). Related: Sabbatartianism.