The most common and most likely answer to this crossword clue is the 7 letter word OFF-AIR
I've seen this crossword clue in Financial Times
O
F
F
-
A
I
R
Buddy explains!

The straight part
We know that "Not broadcasting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not broadcasting = off-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.
What does OFF-AIR mean?
OFF-AIR adjective- Not broadcast on radio or television.
- Pertaining to a radio or television station that is completely shut down.