Butcher's knives (8)
I believe the answer is:
cleavers
'butcher's knives' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for cleavers that I've seen before include "Butchers' tools" , "Chopper's" , "Heavy tools to chop meat" , "Butchers' knives" , "goosegrass" .)