黒くろ々ぐろ

adverb, adverb taking the 'to' particle, noun

deep black; jet black

Describes something that is intensely, vividly black. Often used with と or as an adverbial phrase to modify verbs like 光る, 輝く, or 染まる.

• 彼かれの髪かみは黒くろ々ぐろと輝かがやいていた。

  His hair shone deep black.

• 夜よ空ぞらに黒くろ々ぐろとした雲くもが広ひろがった。

  Jet-black clouds spread across the night sky.