Thrash from French heavy metal artist's empty (6)
I believe the answer is:
Here is my best explanation:
'thrash' is the definition.
'from french heavy metal artist's empty' is the wordplay.
'from french' becomes 'de' (French for 'from').
'heavy metal' becomes 'fe' (chemical symbol for iron).
'empty' means to remove the middle letters.
'artist' with its middle taken out is 'at'.