diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index f97a2e898a..511cb34efa 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -2249,9 +2249,9 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 				_doing_it_wrong(
 					'register_taxonomy',
 					sprintf(
-						/* translators: 1. The taxonomy name, 2. The property name, either rest_base or name. */
+						/* translators: 1. The taxonomy name, 2. The property name, either 'rest_base' or 'name'. */
 						__( 'The "%1$s" taxonomy "%2$s" conflicts with an existing property on the REST API Posts Controller. Specify a custom "rest_base" when registering the taxonomy to avoid this error.' ),
-						$base,
+						$taxonomy->name,
 						$taxonomy_field_name_with_conflict
 					),
 					'5.4.0'