knuckle
noun [ C ] uk/ˈnʌk.əl/ us/ˈnʌk.əl/
C2 指节;（尤指）掌指关节
one of the joints in the hand where your fingers bend, especially where your fingers join on to the main part of your hand
Idiom
near the knuckleidiom UK informal 近乎下流，近乎猥亵
about sex and therefore likely to offend people
Some of his jokes were a bit near the knuckle. 他说的一些笑话有点近乎下流。