rap someone's knuckles

Verb

 * 1)  to tap one's knuckles on an object such as a desk or wall to attract attention or as a signal of commmunication.
 * 2)  to give someone a punishment.
 * 3)  to strike someone on the back of the hand usually as a method of punishment.
 * 1)  to give someone a punishment.
 * 2)  to strike someone on the back of the hand usually as a method of punishment.
 * 1)  to strike someone on the back of the hand usually as a method of punishment.
 * 1)  to strike someone on the back of the hand usually as a method of punishment.