More than surprise (4)
I believe the answer is:
stun
'more than surprise' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for stun that I've seen before include "Confound" , "Knock into a semi-conscious state" , "'Shock, daze (4)'" , "Nuts (anag)" , "Knock unconscious" .)