9 across
Last
part
of
book,
perhaps,
some
find
exciting
(5)
Last part of book, perhaps, some find exciting (5)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
The answer is tucked away inside the clue: Last part of book, perhaps is what an index is, and the word "some" signals a hidden answer lurking in "fINDEXciting", where INDEX runs across find exciting.