Tool for cutting grain (6)
I believe the answer is:
sickle
'tool for cutting grain' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sickle that I've seen before include "Cutting farming tool" , "Corn-cutting tool" , "Corn-cutting blade" , "field-worker being a trimmer" , "Tool for cutting grain" .)