Hide a Product Category from WooCommerce Shop

To hide a product category from your WooCommerce shop, add the following code to your functions.php file and replace xxxxxx with the slug of the category you want to hide:

function custom_pre_get_posts_query( $q ) {
 
	if ( ! $q->is_main_query() ) return;
	if ( ! $q->is_post_type_archive() ) return;
	
	if ( ! is_admin() && is_shop() ) {

		$q->set( 'tax_query', array(array(
			'taxonomy' => 'product_cat',
			'field' => 'slug',
			'terms' => array( 'xxxxxx' ),
			'operator' => 'NOT IN'
		)));
	
	}
 
	remove_action( 'pre_get_posts', 'custom_pre_get_posts_query' );
 
}
add_action( 'pre_get_posts', 'custom_pre_get_posts_query' );

For more on WooCommerce categories, see Check if a Product Belongs to a Specific Category.