In WordPress, each user type have different capability. Sometimes, we want to change these capability and the most easiest way to do that is to remove what they can see when they logged in. Especially when someone wants to change WordPress into a powerful CMS and remove certain admin menu without touching the core system. In most CMS, there are so much restriction on their core system that makes it really inflexible. Unlike other system, WordPress is able to modify their core codes using plugin without affecting the fundamental codes in WordPress. Hence, we can continue to upgrade our system without having to worry about updates that will kill your modification. In this article, i will show you how i remove WordPress admin menu using plugin style without affecting WordPress Core codes.

WordPress Admin Menu

If you are able to dig into WordPress code, you will notice that their menu is created by a single function using two global variables as parameter. You can easily find this code located at wp-admin/menu-header.php, line 157-158.

Source: http://hungred.com/how-to/remove-wordpress-admin-menu-affecting-wordpress-core-system/