A brothel — a building where men pay for sex. The plain, everyday, rather rough word for it. English has a ladder of words for this place: 'brothel' is the neutral one you would see in a news report or a history book; 'whorehouse' is blunt and coarse, because it is built on 'whore', which is an old and insulting word for a woman who sells sex. So the word does not just name the place — it carries contempt, and that contempt lands on the women. That matters for you as a learner. You need to be able to READ this word: it turns up in novels, in films, in songs, in history writing about old port towns and the American West. You almost certainly do not need to SAY it. If you ever have to talk about the topic in English — in a class, at work, in an exam — use 'brothel'. The word is mostly American in flavour; British writing tends to reach for 'brothel' or older slang. In writing about modern policy, people now say 'sex work' and 'sex workers', and avoid this whole family of words on purpose.

妓院、娼館（粗俗用語；中性、正式的說法用 brothel）