Himalayan monster (4)
I believe the answer is:
yeti
'himalayan monster' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yeti that I've seen before include "Hairy recluse" , "Mysterious Himalayan creature" , "whose existence is unconfirmed" , "Your claim to have seen one wouldn't be believed" , "something abominable" .)