The most common and most likely answer to this crossword clue is the 12 letter word OPEN-MOUTHED
I've seen this crossword clue in The Times
O
P
E
N
-
M
O
U
T
H
E
D
Buddy explains!

The straight part
We know that "Surprised-looking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case surprised-looking = open-mouthed.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 OPEN-MOUTHED mean?
OPEN-MOUTHED adjective- Talkative, speaking freely.
- With the mouth open.
- Gaping in surprise, wonder or astonishment.