Gabby, endlessly demanding girl about five (9)
I believe the answer is:
'gabby' is the definition.
(gab can mean to talk a lot)
'endlessly demanding girl about five' is the wordplay.
'endlessly' means to remove the last letter.
'demanding' becomes 'tall' (as in a 'tall order').
'girl' becomes 'katie' (woman's name).
'about' means one lot of letters goes inside another.
'five' becomes 'V' (Roman numeral).
'tall' with its final letter taken away is 'tal'.
'katie' going around 'v' is 'kative'.
(Other definitions for talkative that I've seen before include "Inclined to speak" , "Gabby" , "Chatty" , "of many words" , "Garrulous, loquacious" .)