inner sanctum
Definitions
A private, exclusive, or secret place to which only a select few have access.
The most intimate or innermost part of a person's thoughts or feelings.
Examples
Only the most trusted advisors were permitted to enter the king's inner sanctum.
She retreated to the inner sanctum of her studio to focus on her painting without any distractions.
Synonyms
private retreat holy of holies secret chamber inner circle sanctuary