| crack up 1 (informal 非正式) to be unable to deal with pressure and so lose control and become mentally ill （由于不能应付压力而）失控，精神崩溃: He cracked up when his wife left him. 他的妻子一离开他，他便精神崩溃。 2 (slang 俚语) to suddenly start laughing, especially when you should be serious 突然大笑（尤指在应该严肃的时候） |