Lets her stray in sanctuary (7)
I believe the answer is:
shelter
'sanctuary' is the definition.
(a shelter is a place of sanctuary)
'lets her stray' is the wordplay.
'stray' indicates anagramming the letters.
'lets'+'her'='letsher'
'letsher' anagrammed gives 'SHELTER'.
'in' acts as a link.
(Other definitions for shelter that I've seen before include "Monk's hood" , "Place of refuge" , "'Refuge, cover (7)'" , "Place offering protection" , "Protection from bad weather or danger" .)