Dart in dartboard, a shocker (4)
I believe the answer is:
dash
'dart' is the definition.
('dash' can be a synonym of 'dart')
'in dartboard a shocker' is the wordplay.
'in' says the answer is hidden in the clue.
'DASH' is hidden in the letters of 'dartboard a shocker'.
(Other definitions for dash that I've seen before include "Short race run at top speed" , "Run quickly - little taste - hyphen" , "DOG" , "Dart" , "Stylish vigour; frustrate (hopes)" .)