Harvester (6)
I believe the answer is:
reaper
'harvester' is the definition.
(I know that harvester can be written as reaper)
This is the entire clue.
(Other definitions for reaper that I've seen before include "Harvester - death is a grim one" , "Farm worker" , "Wordsworth's was Solitary" , "being grim when you're late" , "Crop harvester" .)