Without hesitation battered fish is put in front of fellow officer (7)
I believe the answer is:
sheriff
'officer' is the definition.
(thesaurus)
'without hesitation battered fish is put in front of fellow' is the wordplay.
'without' indicates putting letters inside.
'hesitation' becomes 'er'.
'battered' indicates an anagram.
'is put in' indicates putting letters inside (instruction to solver).
'front of' suggests taking the first letters.
The initial letter of 'fellow' is 'f'.
'fish' is an anagram of 'shif'.
'er' placed within 'shif' is 'sherif'.
'sherif' placed around 'f' is 'SHERIFF'.
(Other definitions for sheriff that I've seen before include "Scottish judge" , "Chief officer of the Crown in a county" , "Crown's county officer" , "US law-enforcement officer" , "Lawman of the wild west" .)