The most common and most likely answer to this crossword clue is the 10 letter word BACKBITING
I've seen this crossword clue in The Times
B
A
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K
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Buddy explains!
The straight part
We know that "such spiteful talk!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case such spiteful talk! = backbiting.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 BACKBITING mean?
BACKBITING noun- The action of slandering a person without that person's knowledge.
- To make spiteful slanderous or defamatory statements about someone.
- To attack from behind or when out of earshot with spiteful or defamatory remarks.
- To speak badly of an absent individual.
- Slanderous or speaking badly, especially of a person without that person's knowledge.