Beast's hideaway (4)
I believe the answer is:
lair
(Other definitions for lair that I've seen before include "Rail about wild animal's home" , "Wild animals' habitation" , "Study" , "secluded spot?" , "Private place of seclusion" .)
I believe the answer is:
lair
(Other definitions for lair that I've seen before include "Rail about wild animal's home" , "Wild animals' habitation" , "Study" , "secluded spot?" , "Private place of seclusion" .)