The most common and most likely answer to this crossword clue is the 9 letter word HALLOWEEN
I've seen this crossword clue in The Guardian
H
A
L
L
O
W
E
E
N
More clues leading to the result HALLOWEEN
- None sitting in dining-room: little point in celebration
- Welcome little new for traditional occasion
- When kids knock, greeting tiny one in the middle
- He let in English nationalist for celebration
- Passage ceded regularly in own sweet time
- Greeting small number at festival
- Almost agreed to be embraced by female at festive occasion
- Greeting Little Nell primarily in annual celebration
- Female briefly permitted to join in autumn celebration
- Time for children to tour neighbourhood — mostly permitted when woman’s about
Buddy explains!
The straight part
We know that "festive occasion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case festive occasion = halloween.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.