Talk, chatter (3)
I believe the answer is:
jaw
I believe this is a double definition.
'talk' is the first definition.
(jawing is a kind of talking)
'chatter' is the second definition.
(synonyms)
(Other definitions for jaw that I've seen before include "Facial bone" , "Natter - mandible" , "Talk incessantly" , "Chat" , "Part of the head" .)