Skinhead perhaps receives accidental punishment (5,5,5)
I believe the answer is:
short sharp shock
'skinhead' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for short sharp shock that I've seen before include "Correction" , "Number one cut, with gel" .)