Index: wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
===================================================================
--- wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php	(revision 39408)
+++ wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php	(working copy)
@@ -446,7 +446,7 @@
 		}
 
 		if ( ! comments_open( $post->ID ) ) {
-			return new WP_Error( 'rest_comment_closed', __( 'Sorry, comments are closed on this post.' ), array( 'status' => 403 ) );
+			return new WP_Error( 'rest_comment_closed', __( 'Sorry, comments are closed for this item.' ), array( 'status' => 403 ) );
 		}
 
 		return true;