noun
Refers to the English Protestants of the 16th–17th centuries who sought to purify the Church of England. Also used metaphorically for someone with strict moral views.
清教徒たちは信仰の自由を求めてアメリカへ渡った。
The Puritans crossed to America seeking religious freedom.
Compound of 清 (sei, 'pure') + 教徒 (kyōto, 'believer, adherent of a religion'). A straightforward calque of English 'Puritan'.