The most common and most likely answer to this crossword clue is the 10 letter word BEWILDERED
I've seen this crossword clue in The Times
B
E
W
I
L
D
E
R
E
D
Buddy explains!

The straight part
We know that "Surprised" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case surprised = bewildered.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 BEWILDERED mean?
BEWILDERED verb- To confuse, disorientate, or puzzle someone, especially with many different choices.
- Baffled, confused, mystified, at a loss, not thinking clearly, or uncertain.