Shoot rabbit circling river (6)
I believe the answer is:
sprout
'shoot' is the definition.
(I know that shoot can be written as sprout)
'rabbit circling river' is the wordplay.
'rabbit' becomes 'spout' (both can mean to talk excessively).
'circling' is an insertion indicator (circling can mean going around or containing).
'river' becomes 'r' (abbreviation for river).
'spout' going around 'r' is 'SPROUT'.
(Other definitions for sprout that I've seen before include "Burgeon" , "Produce shoots; vegetable" , "Germinate" , "Grow; vegetable" , "Develop new growth" .)