The term "more umbral" refers to something that is darker, more obscure, or less illuminated. Its antonyms are words that denote the opposite meaning. For instance, "bright," "luminous," "radiant," "shiny," and "glowing" are antonyms for "more umbral." These words have a positive connotation and denote light, clarity, and brightness. Moreover, "clear," "visible," "illuminated," "transparent," and "lucid" are also antonyms for "more umbral," as they denote clarity, transparency, and visibility. In contrast, the word "more umbral" is used to describe something that is shrouded in darkness, gloom, or obscurity.