"Glisteningly" refers to something that shines or glimmers brightly. The antonyms for this word are dull, matte, and opaque. These terms indicate a lack of shine, sparkle, or brilliance. Other antonyms include tarnished, grimy, and murky. These words describe objects that are dirty or have lost their brightness due to age or wear. Similarly, a lack of luster or illumination can also be associated with words like cloudy, overcast, or dark. In essence, the antonyms for "glisteningly" represent the opposite of brightness and radiant shine, often indicating a sense of dullness, opacity, or lack of clarity.