Add body class based on custom taxonomy term

body-class-custom-taxonomy-term.php

<?php

function add_taxonomy_term_as_body_classes( $classes ) {
	global $post;
	$terms = wp_get_post_terms($post->ID, '[taxonomy]', array("fields" => "all"));
	foreach ($terms as $class ) {
		$classes[] = $class->slug;
	}
	return $classes;
}

add_filter('body_class','add_taxonomy_term_as_body_classes');