The most common and most likely answer to this crossword clue is the 9 letter word MAILSHOTS
I've seen this crossword clue in The Guardian
M
A
I
L
S
H
O
T
S
Buddy explains!
The straight part
We know that "publicity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case publicity = mailshots.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 MAILSHOTS mean?
MAILSHOTS noun- Bulk advertising sent through the post/mail.