The most common and most likely answer to this crossword clue is the 6 letter word WITTER
W
I
T
T
E
R
Buddy explains!

The straight part
We know that "babble pointlessly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case babble pointlessly = witter.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 WITTER mean?
WITTER adjective- Knowing, certain, sure, wis.
- To speak at length on a trivial subject.
- To make sure, inform, or declare.