ivory tower

Từ điển Oxford Advanced Learner 8th

ˌivory ˈtower BrE NAmE noun (disapproving)
a place or situation where you are separated from the problems and practical aspects of normal life and therefore do not have to worry about or understand them
•academics living in ivory towers

Word Origin:
[ivory tower] early 20th cent.: translating French tour d'ivoire, used by the writer Sainte-Beuve.