Otter's lair (4)
I believe the answer is:
holt
'otter's lair' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for holt that I've seen before include "Otter's den" , "Otter's burrow" , "Otterden" , "on the Dee south of Chester" , "Otter's lair" .)