Grinds (5)
I believe the answer is:
mills
'grinds' is the definition.
('mill' can be a synonym of 'grind')
This is the entire clue.
(Other definitions for mills that I've seen before include "''Among these dark Satanic ...'' (William Blake)" , "Bomb" , "Sir John - - (films)" , "See 7" , "factories" .)