MySQL does not have any SQL commands or internal mechanisms for
- making an individual database unavailable / offline
- moving an individual database
Thtis being the case, how can you take an individual database offline?
This may not be a suitable answer, but would achieve your goal...
What about, for the time you want it offline, renaming the database? This way, whatever application you have accessing the data would fail to connect to the database.
Thank you for your interest in this question.
Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.
Would you like to answer one of these unanswered questions instead?