Room to relax in (3)
I believe the answer is:
den
'room to relax in' 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 "Wild animal's lair" , "Hidden lair of an animal" , "Habitation of wild animals (3)" , "Animal's lair or gent's study" , "Hideaway" .)