knuckle down 1. 〈口〉开始认真工作，努力工作 The term is almost over so you'd better knuckle down and study. 学期即将结束，你还是专心致志读书为好。 They chatted idly for a few moments then each knuckled down to work. 他们闲扯了一会儿，然后各自埋头工作。 He knuckled down to finding the answer. 他开始认真寻求答案。 2. 屈服 He would not knuckle down under their attacks. 他不会屈服于他们的攻击。 3. (打玻璃弹子时)以指节贴地面