An archdeacon is a priest of high rank in the Anglican Church — the Church of England and the churches in its family, including the one in Taiwan. He or she works under a bishop. The bishop is responsible for a whole church area; the archdeacon does much of the day-to-day looking-after of the churches and priests in part of that area, and may visit, advise, and report problems upward. It is a real title with a real job, not a polite way of saying “an important priest.” You almost only meet it in that church world, or in older English stories about parish life. Though actually the Roman Catholic Church once had archdeacons too, that office has largely faded there; the word you still hear in English belongs mainly to Anglican (and a few similar) churches. People sometimes stretch it to mean “any rather senior church person,” but that is loose talk.