The most common and most likely answer to this crossword clue is the 6 letter word JABBER
I've seen this crossword clue in The Guardian
J
A
B
B
E
R
Buddy explains!

The straight part
We know that "Babble" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case babble = jabber.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 JABBER mean?
JABBER noun- Rapid or incoherent talk, with indistinct utterance; gibberish.
- To talk rapidly, indistinctly, or unintelligibly; to utter gibberish or nonsense.
- To utter rapidly or indistinctly; to gabble.
- One who or that which jabs.
- A kind of hand-operated corn planter.