the.com/missionary

means A member of a religious group sent out to spread their faith and often provide education or aid in other communities; also, informally, the plain, face-to-face position that needs no explanation.

from From Latin 'missio' — a sending — via French 'mission,' rooted in 'mittere,' to send. The religious sense came first: 16th–17th century Catholic orders coined 'missionary' for those sent abroad to spread the faith. The bedroom sense is much later slang, popularly (though shakily) traced to the idea of missionaries abroad instructing local populations toward a single 'approved' position — a tidy story, but more folklore than documented fact; its actual rise in English usage dates to the 20th century.