Animal lair (3)
I believe the answer is:
den
'animal 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 "Habitation of wild animals (3)" , "Animal's home or gent's study" , "Cave" , "Animal habitation" , "Animal's lair or man's study" .)