Surprise shots in a melee (8)
I believe the answer is:
astonish
'surprise' is the definition.
(astonishing is a kind of surprising)
'shots in a melee' is the wordplay.
'melee' indicates anagramming the letters.
'shots'+'in'+'a'='shotsina'
'shotsina' with letters rearranged gives 'ASTONISH'.
(Other definitions for astonish that I've seen before include "Dumbfound" , "Floor" , "Take by surprise" , "Confound" , "are staggering" .)