The most common and most likely answer to this crossword clue is the 7 letter word EDITION
I've seen this crossword clue in The Times
E
D
I
T
I
O
N
More clues leading to the result EDITION
- Inciting rebellion, no small issue
- Rabble-rousing lacks initial impression
- Rebellion sacrificing small volume
- Incitement to rebellion at first dismissed as an issue
- With leader gone, political and social agitation is an issue
- Rabble-rousing lacks its initial impression
- Treasonous speech missing introduction creates issue
- Treason not the first issue
- Issue with electronic speech, not constant
- Incitement to riot? No small issue
Buddy explains!

The straight part
We know that "impression" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case impression = edition.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 EDITION mean?
EDITION noun- A written work edited and published, as by a certain editor or in a certain manner.
- The whole number of copies of a work printed and published at one time.
- A particular instance of an event.