na-adjective, noun which may take the genitive case particle 'no', noun
Describes a pale or pallid appearance, often used for complexion, light, or color. Can be used as a noun or adjectivally with な or の.
彼は病気で顔が蒼白だった。
His face was pale from illness.
Pale moonlight illuminated the room.
蒼白 is a formal, often medical term for facial pallor, while 真っ青 is the everyday, vivid way to describe someone turning white with shock or fear.
蒼白 is a more literary or medical noun for pallor, often used as 顔面蒼白になる, whereas 青ざめる is the everyday verb for someone's face losing color.
蒼白 describes the face turning pale (e.g. from shock or illness), the opposite of 紅潮's reddening.
Compound of 蒼 (sō, 'blue' or 'pale') and 白 (haku, 'white'). The exact historical derivation is uncertain, but the combination naturally conveys paleness.