Wiktionary
untextured
a. To which a texture has not been applied.
Usage examples of "untextured".
An opaque cloud of black, featureless, untextured, taller than a man, a nullity with a voice.
And the voices, and if he'd been able to move, he would have turned and run after those voices, anything, anything to touch and be close with something that was anything, that wasn't the blackness and the untextured warmth.
Two lanterns hung on the walls, creating a pall of smoke that clung to the low, untextured ceiling.