The default declaration for the WordPress is following:
define(‘WP_DEBUG’, false);
But in some cases some WordPress installation need much more to hide due to install of a incompatible plugin or theme. If the previous code doesn’t work then you may use the following code.
Try inserting this in your index.php
error_reporting(0);
ini_set(‘display_errors’, 0);
Or this in .htaccess
# supress php errors
php_flag display_startup_errors off
php_flag display_errors off
php_flag html_errors off
php_value docref_root 0
php_value docref_ext 0