The word "more sunbeamy" refers to a bright and cheerful atmosphere that is full of sunshine. Its antonyms, on the other hand, are words that describe a gloomy and dark atmosphere. These antonyms include somber, bleak, cloudy, overcast, dim, and shadowy. They are the opposite of the word "sunbeamy" in that they convey a sense of sadness, melancholy, and dullness. While "more sunbeamy" describes a day filled with warmth and happiness, its antonyms describe a day that is cold and dreary. Therefore, it is important to use these antonyms carefully to convey the right message and tone in writing.