WordPress at a glance
action is not described

delete_user action-hook . WP 2.0.0

Fires immediately before a user is deleted from the database.

Usage

add_action( 'delete_user', 'action_function_name_3466', 10, 2 );
function action_function_name_3466( $id, $reassign ){
	// action...
}
$id(int)
ID of the user to delete.
$reassign(int/null)
ID of the user to reassign posts and links to.
Default: null, for no reassignment

Where the hook is called

wp_delete_user()
wp-admin/includes/user.php 334
do_action( 'delete_user', $id, $reassign );

Where the hook is used (in WP core)

Does not used.