Being in the natural or original color.(adjective)
Of only one color.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "self-colored" in a sentence
""Self-colored cats" are entirely of one color, which may vary in different cats, but must never be mixed in the same cat, nor even shaded into a lighter tone on the animal; and whether this color be black, blue, red, or yellow, the self-colored cat should have a rich deep tint."
"The black and white, yellow and white, blue and white, and in fact, any self-colored and white cat is a mixture of the other breeds."
"There is also a fine short-haired cat coming from Russia, usually self-colored."