hide_wc_category_from_shop

functions.php

<?php

/**
 * Show products only of selected category.
 */
function get_subcategory_terms( $terms, $taxonomies, $args ) {
 
	$new_terms 	= array();
	$hide_category 	= array( 126 ); // Ids of the category you don't want to display on the shop page
 	
 	  // if a product category and on the shop page
	if ( in_array( 'product_cat', $taxonomies ) && !is_admin() && is_shop() ) {

	    foreach ( $terms as $key => $term ) {

		if ( ! in_array( $term->term_id, $hide_category ) ) { 
			$new_terms[] = $term;
		}
	    }
	    $terms = $new_terms;
	}
  return $terms;
}
add_filter( 'get_terms', 'get_subcategory_terms', 10, 3 );

Hi the above is correct only for the shop page. If you are in the product page the categories will not be hidden. You will also loose the original order of the categories defined in the category setting page.
Your code could be improved like following:

function get_subcategory_terms( $terms, $taxonomies, $args ) {
        $new_terms 	= array();
        $hide_category 	= array( 126 ); // Ids of the category you don't want to display on the shop page
        //use an array to sort categories as per original order
        $sorted_menu = array();
     	// if a product category and on the shop page and even in the product page (class_exists("Woocommerce"))
    	if ( in_array( 'product_cat', $taxonomies ) && !is_admin() && (is_shop() || class_exists('Woocommerce'))  ) {
    	    foreach ( $terms as $key => $term ) {
                 
                 if ( ! in_array( $term->term_id, $hide_category ) ) {
                      $new_terms[] = $term;
                      //add order key to array to sort
                      $sorted_menu[$key] = get_term_meta($term->term_id,'order',true);
    		 }
    	    }
            //resort new array with original order
            array_multisort( $sorted_menu, SORT_ASC, $new_terms );
    	    $terms = $new_terms;
    	}
     return $terms;
}

add_filter( 'get_terms', 'get_subcategory_terms', 10, 3 );

Also if you want to remove the category page of the hidden category you have to add the following (otherwise url http://yourdomain.com/category/category_slug will be still visible):

function check_category_is_disabled(){
      //check if is the category page
      $hide_category 	= array( 126 ); // Ids of the category you don't want to display on the shop page
      if ( is_product_category() ){
  	    global $wp_query;
  	    $cat = $wp_query->get_queried_object();
            //check if current category is disabled
            if ( ! in_array( $cat->term_id, $hide_category ) ) { 
                echo '<style>.page-title { display:none; }</style>';
                $wp_query->set_404();
                status_header( 404 );
                get_template_part( 404 );
                exit();
            }
      }
}

add_action( 'woocommerce_archive_description',  'check_category_is_disabled' ,10,1);