頭あたまが真まっ白しろになる

expression, godan verb (-ru)

go blank; panic and can't think

Describes a mental state where one's mind goes completely blank, often due to shock, panic, or extreme pressure. The image is of the head turning pure white, empty of thoughts.

• 試し験けん中ちゅうに頭あたまが真まっ白しろになって、何なにも書かけなかった。

  During the exam my mind went blank and I couldn't write anything.

• 突とつ然ぜんの質