noun
total darkness; utter darkness
A literary yojijukugo meaning pitch-black darkness, as dark as a moonless night. Rare in modern conversation; mostly encountered in classical or poetic contexts.
洞窟の中は如法暗夜で、一歩も先が見えなかった。
Inside the cave it was pitch-dark, and I couldn't see a step ahead.
A yojijukugo combining 如法 (here meaning 'like' or 'as if') and 暗夜 (dark night), literally 'like a dark night'. The exact historical derivation is uncertain; it is a set phrase used in classical Japanese.