Knight in Muscat going round sacred place (7)
I believe the answer is:
sanctum
'sacred place' is the definition.
(I've seen this before)
'knight in muscat going round' is the wordplay.
'knight' becomes 'n' (chess).
'in' indicates putting letters inside.
'going round' indicates an anagram.
'muscat' anagrammed gives 'sactum'.
'n' inserted inside 'sactum' is 'SANCTUM'.
(Other definitions for sanctum that I've seen before include "Sacred or safe place" , "Private place, may be inner" , "A person's private room, often inner" , "Inviolable retreat" , "Place of total privacy" .)