The term "unilluminated" typically means something that is dark, dim, or lacking light. Its antonyms include bright, illuminated, lit, radiant, and shining. Other words that convey the opposite meaning of "unilluminated" include luminous, glaring, dazzling, vivid, and sparkling. These words suggest a sense of brightness and clarity, indicating a situation or object that is well-lit and easy to see. Antonyms like illuminated and radiant are frequently used to describe a place or an atmosphere that is filled with light and energy. Conversely, unilluminated spaces are often associated with gloom, obscurity, and mystery.