The most common and most likely answer to this crossword clue is the 4 letter word BLAB
I've seen this crossword clue in The Times
B
L
A
B
More clues leading to the result BLAB
- Vestment returned by bishop let out
- Gossip, blatantly lying, answering back initially
- State secrets held in British workshop?
- State secrets?
- Spill secrets of British research facility
- Black dog let out
- Talk in second-class facility
- Chatter in workplace after introduction of bonuses
- Spill the beans about Blair’s leadership and his party
- Sing ‘Bachelor Boy’ when daughter’s born
Buddy explains!

The straight part
We know that "Gossip" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gossip = blab.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 BLAB mean?
BLAB noun- One who blabs; a babbler; a telltale; a gossip or gossiper.
- Gossip; prattle.
- To tell tales; to gossip without reserve or discretion.