The most common and most likely answer to this crossword clue is the 11 letter word MESMERISING
M
E
S
M
E
R
I
S
I
N
G
Buddy explains!
The straight part
We know that "Fascinating" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fascinating = mesmerising.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 MESMERISING mean?
MESMERISING verb- To exercise mesmerism on; to affect another person, such as to heal or soothe, through the use of animal magnetism.
- To spellbind; to enthrall.