The most common and most likely answer to this crossword clue is the 9 letter word CHATTERER
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More clues leading to the result CHATTERER
- Caught one at tea party with Queen that’s a fast talker
- Gossip: mad figure in church heading for Rector
- One might be very cold and also a gossip
- Mad fellow in playground rolling around, one who is 7
- Mad man in church, right type to distract congregation?
- Gossip’s indecent retreat after church
- Milliner in play area rebuffed idle gossiper
- Mad person in church, beginning to rage — what a gossip!
- Church retreat changed talkative type
Buddy explains!

The straight part
We know that "what a gossip!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what a gossip! = chatterer.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CHATTERER mean?
CHATTERER noun- A person who chatters; a chatterbox.
- Any of several passerine birds, mostly from South America; especially the cotingas.