noun, noun or participle which takes 'suru', intransitive verb
Literary or formal noun and suru-verb meaning a sudden feeling of surprise or astonishment. Rare in everyday speech; 驚き (おどろき) is the common equivalent.
その知らせに彼は一驚した。
He was taken by surprise at the news.
一驚のあまり言葉を
I was so astonished that I was at a loss for words.