Charge head of racket, and assistant, from what we hear (4)
I believe the answer is:
raid
'charge' is the definition.
(thesaurus)
'head of racket and assistant from what we hear' is the wordplay.
'head of' suggests taking the first letters.
'and' is a charade indicator (letters next to each other).
'assistant' becomes 'aide' (aide is a kind of assistant).
'from what we hear' indicates a 'sounds like' (homophone) clue.
The initial letter of 'racket' is 'r'.
'aide' is a homophone of 'aid'.
'r'+'aid'='RAID'
(Other definitions for raid that I've seen before include "Sally" , "Search by police without warning" , "Sudden short attack" , "Inroad" , "Rifle" .)