Book about Scottish island on loch shows feeling (9)
I believe the answer is:
emotional
'feeling' is the definition.
(I've seen this before)
'book about scottish island on loch' is the wordplay.
'book' becomes 'tome' (a tome is a book).
'about' is a reversal indicator.
'scottish island' becomes 'Iona' (island of the Hebrides).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'loch' becomes 'l'.
'tome' reversed gives 'emot'.
'emot'+'iona'+'l'='EMOTIONAL'
'shows' acts as a link.
(Other definitions for emotional that I've seen before include "Dramatic" , "Moving" , "Passionate" , "Arousing strong feelings" , "Showing strong feelings" .)