Cimmerian and Stygian

Cimmerian adjective - Causing or marked by an atmosphere lacking in cheer.

Stygian and cimmerian are semantically related in hellish topic. In some cases you can use "Stygian" instead an adjective "Cimmerian", when it comes to topics like lack of light.

Stygian adjective - Being without light or without much light.

Cimmerian and stygian are semantically related in hellish topic. You can use "Cimmerian" instead an adjective "Stygian", if it concerns topics such as crepuscular, lack of light.