undecorated vs unadorned

undecorated and unadorned both are adjectives.

Word	Noun	Adjective	Verb	Adverb
undecorated	No	Yes	No	No
unadorned	No	Yes	No	No

As adjectives, undecorated and unadorned are synonyms defined as:

undecorated and unadorned: not decorated with something to increase its beauty or distinction

undecorated (adjective)	unadorned (adjective)
not decorated with something to increase its beauty or distinction	not decorated with something to increase its beauty or distinction