the charms of a uniquely beautiful woman
A classical Chinese-derived yojijukugo describing a woman so beautiful that flowers feel shame and the moon hides. Used in literary or poetic contexts. Variant forms include 閉月羞花 and 羞月閉花.
See also: 閉月羞花 (へいげつしゅうか) · 羞月閉花 (しゅうげつへいか) · 沈魚落雁 (ちんぎょらくがん)
Her beauty is truly worthy of being called 'shuuka heigetsu' (a beauty that shames flowers and hides the moon).
A Japanese ordering of the Chinese beauty idiom 閉月羞花, literally describing beauty that makes the moon hide and flowers feel ashamed.