The most common and most likely answer to this crossword clue is the 9 plus 5 letter word TELEPHONE BOOTH
T
E
L
E
P
H
O
N
E
B
O
O
T
H
Buddy explains!
The straight part
We know that "chat-room?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case chat-room? = telephone booth.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.