Stumble in surprise (7)
I believe the answer is:
stagger
This clue is a double definition.
'stumble' is the first definition.
(I know that stumble can be written as stagger)
'surprise' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for stagger that I've seen before include "Totter" , "Surprise" , "Reel - astound" , "Teeter" , "Reel about; shock" .)