Hide WooCommerce (3.3 and above) default category

woocommerce_hide_default_category.php

<?php

/* Hide WooCommerce default category on the frontend */
add_filter( 'woocommerce_product_subcategories_args', 'woocommerce_hide_default_category' );

function woocommerce_hide_default_category( $args ) {
	$args['exclude'] = get_option( 'default_product_cat' );
	return $args;
}