gnash/næʃ; næʃ/ v[Tn](usu fig 通常作比喻) grind (one's teeth) together as a sign of great emotion （因情绪激动）咬或磨（牙） I was gnashing my teeth with/in rage, ie was extremely angry. 我咬牙切齿愤怒已极.
牛津英汉双解词典