Monstrous loch? (4)

I believe the answer is:
ness
'monstrous loch?' is the definition.
(as in the Loch Ness Monster)
This is all the clue.
(Other definitions for ness that I've seen before include "Loch of monster fame" , "Scottish lake with traditional monster" , "Headland, promontory" , "Headland, cape" , "Scottish Loch famed for monster" .)