### Clue: Master standing to admit dereliction of duty in sanctum sanctorum (6)
### Answer: ADYTUM 
 ### Explanation: Definition: sanctum sanctorum
 **Reversal of**(standing, in a down clue) MA(abbrev. for Master of Arts, say) **containing**(to admit) **anagram of**(dereliction of) DUTY.
Answer:  The most sacred place of worship in an ancient temple, out of bounds to the laity.