There are several synonyms available for the word "night-dark." Some of these include pitch-black, inky, gloomy, dim, murky, shadowy, and darkened. Each of these words effectively conveys a sense of darkness that is typically associated with nighttime. Pitch-black suggests an utter absence of light, while inky evokes the inkiness of the night sky. Gloomy, dim, and murky all suggest a lack of light as well, but also a certain heaviness or weightiness that is often associated with the nighttime. Shadowy and darkened both imply a decrease in light, but also a presence of shadows or partial darkness.