The word "most lightless" refers to something that lacks any kind of light or brightness. Its antonyms are words that mean the opposite, such as "bright," "luminous," "radiant," "lustrous," "shining," "gleaming," "sparkling," "glowing," "illuminated," and "brilliant." These words represent the essence of light and its ability to illuminate and bring life to everything around us. They describe things that are full of brightness and energy, which can instantly uplift our mood and bring a sense of joy and positivity to our lives. So, when searching for the antonyms of "most lightless," use these words to find the right match.