The most common and most likely answer to this crossword clue is the 10 letter word REVELATION
I've seen this crossword clue in The Sunday Telegraph
R
E
V
E
L
A
T
I
O
N
More clues leading to the result REVELATION
- Surprising fact about Victor and Joy
- English verse found in account book
- Twist a handle in to animate display
- Delight following priest’s manifestation of divine will
- Telling about drug, very enlightening experience
- Biblical book provides joy to a clergyman
- Book giving priest great joy
- Festivity at number one — turned up for unveiling
Buddy explains!

The straight part
We know that "enlightening experience" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case enlightening experience = revelation.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 REVELATION mean?
REVELATION noun- The act of revealing or disclosing.
- Something that is revealed.
- Something dramatically disclosed.
- A manifestation of divine truth.
- A great success.