unembellished

From un- +‎ embellished.

unembellished (comparative more unembellished, superlative most unembellished)

1. Plain, unadorned, or simple.

   Synonyms: austere, bare, modest, undecorated, unadorned; see also Thesaurus:unadorned

   Antonyms: adorned, decorate, complicated; see also Thesaurus:gaudy

   • 1941 October, C. Hamilton Ellis, Charles E. Lee, “The Welsh Highland Railway—III”, in Railway Magazine, page 435:

     Thus passed the last of the North Wales Narrow Gauge locomotives, and one of the few American-built locomotives to survive in Great Britain; the sadly cropped though once elegant Russell, and the unembellished yet useful Yankee plug-ugly.