also: みどりがみ
noun
glossy black hair
Only with reading りょくはつ
Literary or poetic term for beautiful, lustrous black hair, often associated with classical descriptions of women. Restricted to reading りょくはつ.
彼女の緑髪は、まるで濡れた烏の羽のように艶やかだった。
Her glossy black hair was as lustrous as a wet crow's feather.
noun
green hair
Used primarily for fictional characters, especially in anime, manga, and games. Reading みどりがみ is common in this context.
そのアニメの主人公は、鮮やかな緑髪が特徴的だ。
The protagonist of that anime is characterized by vivid green hair.
緑 (りょく, 'green') + 髪 (はつ, 'hair'). The reading りょくはつ is on'yomi, while みどりがみ is a kun'yomi compound. The 'glossy black' meaning is a classical usage where 緑 could refer to a deep, lustrous black.