total darkness; pitch darkness
Archaic noun for complete, impenetrable darkness. Not used in modern everyday Japanese; encountered only in classical literature or historical contexts.
In old tales, the forest at night is sometimes described as 'shikiyami' (total darkness).
The exact derivation is uncertain; the kanji 頻 (frequent, repeated) and 闇 (darkness) combine to suggest an overwhelming, pervasive darkness in classical usage.