tax-query
$tax_query = array( 'relation' => 'AND', array( 'taxonomy' => 'section', 'field' => 'term_taxonomy_id', 'operator' => 'NOT EXISTS', ), );
$tax_query = array( 'relation' => 'AND', array( 'taxonomy' => 'section', 'field' => 'term_taxonomy_id', 'operator' => 'NOT EXISTS', ), );