In this post I will show you how to remove «category» from WordPress categories URL, how to remove «tag» from post tags URLs, and how to remove custom taxonomy slugs («product_cat») from term URLs: Here is the main part of thе code, you can insert it into your current theme functions.php
, just do not forget to change taxonomy names/slugs in each function to your own values.
add_filter('request', 'rudr_change_term_request', 1, 1 );
function rudr_change_term_request($query){
$tax_name = 'product_cat'; // specify you taxonomy name here, it can be also 'category' or 'post_tag'
// Request for child terms differs, we should make an additional check
if( $query['attachment'] ) :
$include_children = true;
$name = $query['attachment'];
else:
$include_children = false;
$name = $query['name'];
endif;
$term = get_term_by('slug', $name, $tax_name); // get the current term to make sure it exists
if (isset($name) && $term && !is_wp_error($term)): // check it here
if( $include_children ) {
unset($query['attachment']);
$parent = $term->parent;
while( $parent ) {
$parent_term = get_term( $parent, $tax_name);
$name = $parent_term->slug . '/' . $name;
$parent = $parent_term->parent;
}
} else {
unset($query['name']);
}
switch( $tax_name ):
case 'category':{
$query['category_name'] = $name; // for categories
break;
}
case 'post_tag':{
$query['tag'] = $name; // for post tags
break;
}
default:{
$query[$tax_name] = $name; // for another taxonomies
break;
}
endswitch;
endif;
return $query;
}
add_filter( 'term_link', 'rudr_term_permalink', 10, 3 );
function rudr_term_permalink( $url, $term, $taxonomy ){
$taxonomy_name = 'product_cat'; // your taxonomy name here
$taxonomy_slug = 'product_cat'; // the taxonomy slug can be different with the taxonomy name (like 'post_tag' and 'tag' )
// exit the function if taxonomy slug is not in URL
if ( strpos($url, $taxonomy_slug) === FALSE || $taxonomy != $taxonomy_name ) return $url;
$url = str_replace('/' . $taxonomy_slug, '', $url);
return $url;
}
And do not forget about 301 redirect from old URLs, it is required for your website SEO.
add_action('template_redirect', 'rudr_old_term_redirect');
function rudr_old_term_redirect() {
$taxonomy_name = 'product_cat';
$taxonomy_slug = 'product_cat';
// exit the redirect function if taxonomy slug is not in URL
if( strpos( $_SERVER['REQUEST_URI'], $taxonomy_slug ) === FALSE)
return;
if( ( is_category() && $taxonomy_name=='category' ) || ( is_tag() && $taxonomy_name=='post_tag' ) || is_tax( $taxonomy_name ) ) :
wp_redirect( site_url( str_replace($taxonomy_slug, '', $_SERVER['REQUEST_URI']) ), 301 );
exit();
endif;
The code was tested with different hierarchical and non-hierarchical taxonomies and works great with this permalink settings.

https://rudrastyh.com/wordpress/remove-taxonomy-slug-from-urls.html