gistfile1.txt

add_filter( 'propertyhive_property_query_tax_query', 'remove_sold', 10, 2 );
function remove_sold( $tax_query, $query )
{
    $tax_query[] = array(
        'taxonomy'  => 'availability',
        'terms' => array(15),
        'operator' => 'NOT IN',
    );
    
    return $tax_query;
}