Dotty can and must in refuge (7)
I believe the answer is:
sanctum
'refuge' is the definition.
(I've seen this in another clue)
'dotty can and must' is the wordplay.
'dotty' indicates an anagram.
'and' is a charade indicator (letters next to each other).
'can' after 'must' is 'mustcan'.
'mustcan' is an anagram of 'SANCTUM'.
'in' acts as a link.
(Other definitions for sanctum that I've seen before include "Inviolable retreat" , "sacred space" , "Shrine" , "SECOND PART OF 3" , "somewhere private" .)