Maybe brilliant daughter without domestic staff, running about (7)
I believe the answer is:
diamond
'maybe brilliant' is the definition.
'diamond' can be an answer for 'brilliant' (thesaurus). I'm not certain of the 'maybe' bit.
'daughter without domestic staff running about' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'without' becomes 'no'.
'domestic staff running' becomes 'maid' (I can't explain this - if you can you should give a lot more credence to this answer).
'about' is a reversal indicator.
'd'+'no'+'maid'='dnomaid'
'dnomaid' back-to-front is 'DIAMOND'.
Can you help me to learn more?
(Other definitions for diamond that I've seen before include "Precious stone of pure crystallized carbon" , "Stone - card" , "DOG" , "Precious stone for mad Odin" , "Gemstone - baseball field" .)