The most common and most likely answer to this crossword clue is the 6 letter word PRATED
I've seen this crossword clue in The Daily Telegraph
P
R
A
T
E
D
More clues leading to the result PRATED
Buddy explains!
The straight part
We know that "blabbered" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blabbered = prated.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 PRATED mean?
PRATED verb- To talk much and to little purpose; to be loquacious; to speak foolishly.