VAT is charged primarily for clothing (5)
I believe the answer is:
tunic
'for clothing' is the definition.
(tunic is a kind of clothing)
'vat is charged primarily' is the wordplay.
'vat' becomes 'tun' (I've seen this in another clue).
'primarily' indicates taking the first letters.
The first letters of 'is charged' is 'ic'.
'tun'+'ic'='TUNIC'
(Other definitions for tunic that I've seen before include "Partly uniform" , "Policeman may be in one" , "Belted coat" , "Clobber" , "Close-fitting jacket that's part of a uniform" .)