The word "scintillescent" refers to something that sparkles or shines brightly. Therefore, antonyms for this word would include dull, drab, and lackluster. Other antonyms might include gloomy, dark, or dim, as these words describe environments or objects that are not bright or shiny. Additionally, antonyms for "scintillescent" could also include words that describe materials or surfaces that absorb light, such as matte, opaque, or non-reflective. In everyday language, antonyms for "scintillescent" might be used when describing anything from clothing to artwork to interior design, as well as environmental conditions like a cloudy sky or a poorly lit room.