Grain-cutting tool (6)
I believe the answer is:
scythe
'grain-cutting tool' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for scythe that I've seen before include "One cuts" , "Reaping implement" , "Chesty (anag) -- reaping tool" , "Bladed cropping implement" , "Old farming tool" .)