Prince William's mum
I believe the answer is:
diana
'prince william's mum' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for diana that I've seen before include "She separated from Charles" , "MONKEY" , "Roman goddess of the moon and hunting" , "Roman equivalent of Artemis" , "Dame - Rigg, actress" .)