The most common and most likely answer to this crossword clue is the 9 letter word PERSONALS
P
E
R
S
O
N
A
L
S
Buddy explains!
The straight part
We know that "classified ads" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case classified ads = personals.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 PERSONALS mean?
PERSONALS noun- An advertisement by which individuals attempt to meet others with similar interests.
- A movable; a chattel.