abyssal

/əˈbɪs.əl/
adjective
  1. Relating to the deepest parts of the ocean, typically below 4,000 meters (13,000 feet).
    • The abyssal zone is home to strange, bioluminescent creatures.
    • Only specially designed submarines can survive the abyssal pressure.
    • Abyssal plains cover large areas of the ocean floor.
  2. Extremely deep or profound; like an abyss.
    • The cave had an abyssal darkness that swallowed the light.
    • The novel explores the abyssal depths of human emotion.
    • He felt an abyssal loneliness after moving to a new city.
Synonyms
What does "abyssal" mean? | whatsthatwordmean | whatsthatwordmean