Beginning of Moloch's evil works (4)
I believe the answer is:
mill
'works' is the definition.
(mill is a kind of works)
'beginning of moloch's evil' is the wordplay.
'beginning of' says to take the initial letters.
'evil' becomes 'ill' (I've seen this in other clues).
The first letter of 'moloch' is 'm'.
'm'+'ill'='MILL'
(Other definitions for mill that I've seen before include "(Pepper) grinder" , "Grind (flour)" , "Race a moving influence on this" , "Rob < works" , "There's an old one by the stream, Nellie Dean" .)