The categories at the top of a GeoDirectory listing page come from the GD > Single Taxonomies block (shortcode [gd_single_taxonomies]) in your Details Page template. You can hide all of them with the block settings, or hide only some with a short snippet.

Hide all categories

Edit the page set as the Details Page template in GeoDirectory > Settings > General > Pages. Either remove the GD > Single Taxonomies block, or set its Taxonomy option to Tags so only tags show ([gd_single_taxonomies taxonomy="tags"]).

Hide only some categories

If some of your parent categories are only there as headings, you can stop just those from showing. Find each category’s ID (it shows in the address bar when you edit the category under Places > Categories), then add this snippet with your IDs:

add_filter( 'geodir_details_taxonomies_cat_link', function( $link, $term ) {
	$hidden = array( 12, 15 ); // IDs of the categories to hide.

	if ( in_array( (int) $term->term_id, $hidden, true ) ) {
		return '';
	}

	return $link;
}, 10, 2 );

The listing stays in those categories, so it still shows on their category pages and in search. Only the link on the details page is hidden. You can add the snippet with the Code Snippets plugin.

The other settings of this block, such as the link style and the limit, are covered in GD > Single Taxonomies.