Dimpsy is an unusual word, but it's one that captures a particular time of day when the light is dimming and the darkness is slowly approaching. You might also use the synonym "dusk" to describe this time of day. Other synonyms for dimpsy include "twilight," "evening," and "nightfall." Depending on the individual context, you could also use "gloaming," "sunset," or "sundown" to illustrate the same idea. These words all capture the same sense of soft, subdued light and the transition from day to night. Whether you prefer to use dimpsy or one of these synonyms, they all beautifully convey the ethereal beauty of this special time of day.