Hoarding gold is tax free (8)
I believe the answer is:
exorcise
'free' is the definition.
(to exorcise is to free of demons)
'hoarding gold is tax' is the wordplay.
'hoarding' means one lot of letters goes inside another.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'is tax' becomes 'excise' (I've seen this before).
'or' put inside 'excise' is 'EXORCISE'.
(Other definitions for exorcise that I've seen before include "getting cast out" , "drive away" , "Drive out evil spirit by prayer" , "Expel evil spirit" , "Remove spirits" .)