/'nʌkl; `nʌkl/
n
1 bone at the finger-joint 指节; 指关节
*graze/skin one's knuckles 擦破指关节. =>illus at hand 见hand插图.
2 (of animals) knee-joint, or the part joining the leg to the foot, esp as a joint of meat （指动物）膝关节, 踝; （尤指食用的）肘
*pig's knuckles 猪肘.
3 (idm 习语) a rap on/over the knuckles => rap1.near the `knuckle (infml 口) on the borderline of indecency and therefore likely to offend 近乎下流; 猥亵
*Some of his jokes are a bit too near the knuckle for my taste. 我觉得他有的笑话已近乎淫亵了.

v (phr v) knuckle down (to sth) (infml 口) begin to work seriously (at sth) 开始认真工作
*If you want to pass that exam, you'll have to knuckle down (to some hard work). 你要想考试及格, 就得开始下功夫（苦干）了. knuckle under (infml 口) accept or admit defeat; surrender 屈服; 认输; 投降.