The most common and most likely answer to this crossword clue is the 3 plus 3 letter word HOT AIR
I've seen this crossword clue in The Daily Telegraph
H
O
T
A
I
R
More clues leading to the result HOT AIR
- Shock maybe about old books offering nonsense
- Rubbish musical about Heart of Midlothian
- Erotic song that's supposed to impress listeners
- Piping tune — or just words?
- Guff one has to endure in sauna?
- Shock: describing most of the bible as cobblers
- Nonsense poet regularly appearing in musical
- Balloon filler‘s bunk
- Cover over books of empty talk maybe from 10
- With no love left, misguided lothario makes boastful speech
Buddy explains!
The straight part
We know that "silly talk" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case silly talk = hot air.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.