Whaler's spear (7)
I believe the answer is:
harpoon
'whaler's spear' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for harpoon that I've seen before include "Spear for old whaler" , "Whaler's missile" , "Lance" , "Barbed missile" , "Barbed whaling spear" .)