Boycott with good strike (4)
I believe the answer is:
bang
'strike' is the definition.
('bang' can be a synonym of 'strike')
'boycott with good' is the wordplay.
'boycott' becomes 'ban'.
'with' says to put letters next to each other.
'good' becomes 'g' (abbreviation).
'ban'+'g'='BANG'
(Other definitions for bang that I've seen before include "Hairstyle" , "Strike violently" , "Sound of a gunshot" , "Sudden loud noise like an explosion" , "A loud report or a collision" .)