lose one's nerve

lose one's nerve (third-person singular simple present loses one's nerve, present participle losing one's nerve, simple past and past participle lost one's nerve)

1. To stop doing or fail to do something because one lacks courage.
   • December 7 2022, Simon Shuster, “2022 Person of the Year: Volodymyr Zelensky”, in Time‎:

     Zelensky was adaptable, trained not to lose his nerve under pressure.

• bottle it
• chicken out

• hold one's nerve

• “lose your nerve” (US) / “lose your nerve” (UK) in Macmillan English Dictionary.
• “lose one's nerve”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “lose ones nerve”, in Collins English Dictionary.