[with obj.]grind (one's teeth) together, typically as a sign of anger 咬牙(多表示愤怒) no doubt he is gnashing his teeth in rage. 毫无疑问他正气得咬牙切齿呢。 ■[no obj.](of teeth) strike together; grind (牙齿)互相叩击;磨牙 the dog's jaws were primed to gnash. 那狗正准备要磨牙。
语源
late Middle English: perhaps related to Old Norse gnastan 'a gnashing'