na-adjective, noun
deep blue; bright blue
Describes a vivid, intense blue, often used for clear skies or the sea.
今日は空が真っ青で気持ちがいい。
The sky is deep blue today and it feels great.
真っ青な海を見て感動した
I was moved by the sight of the bright blue sea.
na-adjective, noun
ghastly pale; white as a sheet
Describes a face drained of color due to shock, fear, or illness.
彼はその知らせを聞いて真っ青になった。
He turned ghastly pale upon hearing the news.
彼女は真っ青な顔で立っていた。
She stood there with a face white as a sheet.