The most common and most likely answer to this crossword clue is the 9 letter word STORYBOOK
I've seen this crossword clue in The Times
S
T
O
R
Y
B
O
O
K
More clues leading to the result STORYBOOK
- Unreal level of American reserve
- Fabulous, being blessed with unknown amount in gold reserve
- Fabulous, singular blue and yellow card
- Bird carrying child carrying boy off, love being source of romance
- Romantic from Saskatchewan getting Conservative disapproval?
- Idyllic infant courier accepts nub of royal disapproval
Buddy explains!

The straight part
We know that "Fabulous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fabulous = storybook.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 STORYBOOK mean?
STORYBOOK noun- A book containing stories, especially children's stories.
- As in a story for children; pleasant and idealized, or having a happy conclusion.