Bear's lair (3)
I believe the answer is:
den
'bear's lair' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for den that I've seen before include "Animal lair or gent's study" , "Hideaway" , "Animal shelter" , "Home of the beast" , "Gentleman's study or animal's lair" .)