to feel very angry and upset about sth, especially because you cannot get what you want :
He'll be gnashing his teeth when he hears that we lost the contract.
to feel very angry and upset about sth, especially because you cannot get what you want :
He'll be gnashing his teeth when he hears that we lost the contract.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005