Exclude a Custom Post Type From Search

You may have all post types allowed to show in the search results. However, there are few custom post types like slider on the homepage that aren’t useful to appear in the searches, so you can simply exclude a custom post type from search.

Instructions: Add the following code to the functions.php file of your WordPress theme.

<?php
add_action('init', 'codex_custom_init');
function codex_custom_init()
{

  $args = array(
    'exclude_from_search' => false, // the important line here!
    'public' => true,
    'publicly_queryable' => true,
    'show_ui' => true,
    'show_in_menu' => true,
    'query_var' => true,
    'rewrite' => true,
    'capability_type' => 'post',
    'has_archive' => true,
    'hierarchical' => false,
    'menu_position' => null,
    'supports' => array('title','editor','author','thumbnail','excerpt','comments')
  );
  register_post_type('book',$args);
}
?>

You may also enjoy filtering search by users in WordPress.