extreme amazement or being taken aback; to be astonished or horrified by something unexpected.
彼の突然の辞職にみんなが仰天した。
Everyone was astonished by his sudden resignation.
ニュースでその事件を知り、仰天した。
I was shocked to learn about the incident on the news.
あの値段を見て仰天したよ。
I was taken aback when I saw that price.