HideAdmin module will help you easily rename /admin part of your shop so it will be more secure and safe. You can choose any name you want or take one suggested by the module. In case of any error during renaming process it`s easy to undo any change made by the module and rollback everything to original state.

Please look at the module on demo site
Admin demo user: demo password: demo
navigate to Extensions, open list of Modules, select HideAdmin and press edit button.