The Collaborative International Dictionary
Brownist \Brown"ist\, n. (Med.) One who advocates the Brunonian system of medicine.
Brownist \Brown"ist\, n. (Eccl. Hist.) A follower of Robert Brown, of England, in the 16th century, who taught that every church is complete and independent in itself when organized, and consists of members meeting in one place, having full power to elect and depose its officers.
Wikipedia
The Brownists were English Dissenters or early Separatists from the Church of England. They were named after Robert Browne, who was born at Tolethorpe Hall in Rutland, England, about the middle of the 16th century. A majority of the Mayflower passengers in 1620 were Brownists, and indeed the Pilgrims were known for 200 years as the Brownist Emigration.
Usage examples of "brownist".
Presbyterian, another an Independent, another a Brownist, another an Antimonian, another an Anabaptist, another a Familist, another for Prelatical government, another a Seeker, another a Papist, and the tenth, it may be, an Atheist, and the eleventh a Jew, and the twelfth a Turk?
Presbyterians, Independents, Ranters, Anabaptists, Fifth Monarchy men, Brownists, and a score of other sects, out of whose strife rose the finest regiments that ever formed line upon a field of battle?
The Brownists were followers of Robert Browne, who was such an extreme Puritan he felt he had to leave the Church of England altogether.