Harsh finish (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
ness
(Other definitions for ness that I've seen before include "Loch of monster fame" , "Where you're reputed to see monster" , "Scottish Lough of monster myth" , "Scottish Loch with legendary monster" , "Scottish Loch famed for monster" .)