Sack head of finance in anger (5)
I believe the answer is:
rifle
'sack' is the definition.
(thesaurus)
'head of finance in anger' is the wordplay.
'head of' says to take the initial letters.
'in' is an insertion indicator.
'anger' becomes 'rile' (I've seen this in other clues).
The initial letter of 'finance' is 'f'.
'f' inserted into 'rile' is 'RIFLE'.
(Other definitions for rifle that I've seen before include "Ransack; a weapon" , "Firearm - plunder" , "lock, stock and barrel" , "Shoulder weapon" , "Rummage" .)