You can customize the message shown to user when they access Forbidden web page. This is 403 status code header sent by server to browser.
You don't have permission to access ... on this server.
Apache .... Server ........
Just add this line to your Apache Config file (httpd):
ErrorDocument 403 /forbidden.html
Create file forbidden.html page into your doc_root folder. This web page "forbidden.html" is like normal web page. So you can do whatever you like to do with it.
Related: Access deny a web page