Jabber (6)
I believe the answer is:
gabble
'jabber' is the definition.
(I know that jabber can be written as gabble)
This is the entire clue.
(Other definitions for gabble that I've seen before include "Talk quickly and indistinctly" , "Chatter inarticulately" , "Speak rapidly and incessantly" , "Speak quickly and unclearly" , "rabbit" .)