<?php
$taxonomy_name = 'taxslug'; //タクソノミースラッグ(英数字)を入力
$term_id = 1; //親タームのID(数字)を入力
$termchildren = get_term_children( $term_id, $taxonomy_name );
foreach ( $termchildren as $child ) :?>
 <?php $term = get_term_by( 'id', $child, $taxonomy_name );?>
 <p><a href="<?php echo get_term_link( $child, $taxonomy_name );?>">
    <?php echo $term->slug; //スラッグ名 ?>
    <?php echo $term->name; //ターム名 ?>
 </a></p>
<?php endforeach; ?>