The most common and most likely answer to this crossword clue is the 12 letter word BENEFACTRESS
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result BENEFACTRESS
- Supporter's complaint, on introduction of northern player
- Patron’s complaint about new leading lady
- She sponsors France's best exhibitions at first, somehow
- Complaint about northern player? She provides financial support
- Bishop to sense trouble over truth about female patron
- Sponsor has complaint about new performer
- Generous woman makes complaint about new player
- Complain about northern girl on stage — an angel?
- One must have been in variety with fine female actor as fairy godmother
- One gives complaint purchasing new player
Buddy explains!

The straight part
We know that "fairy godmother" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fairy godmother = benefactress.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BENEFACTRESS mean?
BENEFACTRESS noun- A female benefactor.