A fairy godmother, is a female character in fairy stories who has magical powers and protects one of the main characters.
2. singular noun
If you call a woman your fairy godmother, you are saying in a slightly humorous way that she has been very helpful in your life, often at times when you thought you had problems that could not be solved.
The woman I regarded as my fairy godmother was Sybil. She was wonderful to me.
fairy godmother in British English
noun
1.
a character in certain fairy stories who brings unexpected benefits to the hero or heroine