Learn how to say Knuckling correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word knuckle:
a part of a finger at a joint where the bone is near the surface, especially where the finger joins the hand.
a projection of the carpal or tarsal joint of a quadruped.
a joint of meat consisting of the knuckle of an animal together with the adjoining parts:
a knuckle of pork
[with object] rub or press (something, especially the eyes) with the knuckles.: