Raven-black darkness can be described using various synonyms such as inky darkness, jet-black, pitch darkness, and Stygian darkness. Inky darkness refers to a deep, opaque black color reminiscent of ink. Jet-black signifies a dark color that's analogous to the sheen of jet or coal. Pitch darkness refers to an all-consuming and impenetrable darkness pitch. Lastly, Stygian darkness evokes the darkness of the river Styx from Greek mythology, symbolizing an eternal and foreboding darkness. These synonyms can be used to convey different shades and intensities of darkness, allowing writers to describe the atmospheric conditions that their characters might find themselves in more vividly.