Спрятать админа от другого админа

Replace text with the actual usernames of the users involved. You can also modify this to hide one admin from all other users (except him/herself), or based on user IDs or roles. For WordPress 3.1+.

add_action('pre_user_query','yoursite_pre_user_query');
function yoursite_pre_user_query($user_search) {
  global $current_user;
  $username = $current_user->user_login;

  if ($username == '<USERNAME OF OTHER ADMIN>') { 
    global $wpdb;
    $user_search->query_where = str_replace('WHERE 1=1',
      "WHERE 1=1 AND {$wpdb->users}.user_login != '<YOUR USERNAME>'",$user_search->query_where);
  }
}

источник

или вот тут чуть больший цикл прятанья и админа и некоторой админки. думаю, что по коду разберетесь 🙂

add_action('pre_user_query','yoursite_pre_user_query');
function yoursite_pre_user_query($user_search) {
  global $current_user;
  $username = $current_user->user_login;

  if ($username == 'psm-admin') {
    global $wpdb;
    $user_search->query_where = str_replace('WHERE 1=1',
      "WHERE 1=1 AND {$wpdb->users}.user_login != 'admin'",$user_search->query_where);
  }
}

/*
 * Hide admin menus for non Network Admins
 */
function custom_remove_admin_theme_remove_menus () {
	global $current_user;
	$username = $current_user->user_login;
	if ($username == 'psm-admin') {
		global $menu;
		$restricted = array(
			__( 'Users' ),
		);
		end ( $menu );

		while ( prev( $menu ) ) {
			$value = explode( ' ',$menu[key( $menu )][0] );
			if ( in_array( $value[0] != NULL ? $value[0]: '', $restricted ) ) {
				unset( $menu[key( $menu )] );
			}
		}
	}
}
add_action('admin_menu', 'custom_remove_admin_theme_remove_menus', 10);

/*
 * If user is not a SuperAdmin, when they try to access the below URLs they are redirected back to the dashboard.
 */
function restrict_admin_with_redirect() {
	global $current_user;
	$username = $current_user->user_login;

	$restrictions = array(
		'/wp-admin/users.php',
		'/wp-admin/user-new.php'
	);

	foreach ( $restrictions as $restriction ) {

		if ( $username == 'psm-admin' && $_SERVER['PHP_SELF'] == $restriction ) {
			wp_redirect( admin_url() );
			exit;
		}
	}
}
add_action( 'admin_init', 'restrict_admin_with_redirect' );

function mytest() {
	global $wp_list_table;
	$hidearr = array('wx-admin.php');
	$myplugins = $wp_list_table->items;
		foreach ($myplugins as $key => $val) {
			if (in_array($key,$hidearr))
				unset($wp_list_table->items[$key]);
		}
	}
add_action( 'pre_current_active_plugins', 'mytest' );