The phrase "night-black" is used to describe the darkest shade of black, much like the color of the night sky. However, there are several other synonyms that can be used instead to vary the language used. Some alternatives include "pitch-black," "inky," "ebony," "charcoal," "sable," "jet," "midnight," "shadowy," and "dark as coal." Each of these words can add a different nuance to the color black, painting a more vivid picture when describing objects or environments. These synonyms can be used in creative writing, poetry, or even in everyday conversation to spice up the language used.