Half of them headstrong - hand out punishment (6)
I believe the answer is:
thrash
'hand out punishment' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'half of them headstrong' is the wordplay.
'half of' suggests halving the letters.
'headstrong' becomes 'rash' (I've seen this before).
'them' with half the letters taken is 'th'.
'th'+'rash'='THRASH'
Can you help me to learn more?
(Other definitions for thrash that I've seen before include "wild party" , "Drub" , "Beat heavily, perhaps with whip" , "Lay on - party" , "Flog; party" .)