no-go area
noun /ˌnəʊ ˈɡəʊ eəriə/
/ˌnəʊ ˈɡəʊ eriə/
(especially British English)- an area, especially in a city, which is dangerous for people to enter, or that the police or army do not enter, often because it is controlled by a violent group
禁区（常因被暴力团伙控制） - Some clubs are no-go areas for people over 30.
对于 30 岁以上的人来说，有些俱乐部是禁区。 - (figurative) This subject is definitely a no-go area (= we must not discuss it).
这个话题绝对禁止谈论。
- Some clubs are no-go areas for people over 30.