← BackshareGuessnonluminous/nɑnˈlumənəs/adjectiveNot giving off light; not shining or glowing.The moon is nonluminous; it only reflects light from the sun.Unlike a star, a planet is nonluminous and visible only by reflected sunlight.In the dark cave, the walls were completely nonluminous.SynonymsdimdarkAntonymsbrightglowingluminous