Initially, perhaps, rabbit and talk excessively (5)
I believe the answer is:
prate
This clue could be a double definition.
'initially perhaps rabbit' is the first definition.
'prate' can be an answer for 'rabbit' (I've seen this before). I'm not certain of the 'initially perhaps' bit.
'talk excessively' is the second definition.
(I've seen this in another clue)
'and' is the link.
Can you help me to learn more?
(Other definitions for prate that I've seen before include "Taper (anag.)" , "Talk foolishly - blab" , "Talk long and foolishly" , "Rabbit on" , "Tattle, chatter" .)