keep one's nerve

keep one's nerve (third-person singular simple present keeps one's nerve, present participle keeping one's nerve, simple past and past participle kept one's nerve)

1. To keep one's cool
   • 2017, David Walliams [pseudonym; David Edward Williams], Bad Dad, London: HarperCollins Children’s Books, →ISBN:

     There in crisp fifty-pound notes was the answer to so many of his and his father’s problems. When he thought no one was looking, Frank moved his left foot slowly forward to cover it. If he kept his nerve, he could craftily slide it out of the room.