Book detective showing bite for the most part (5)
I believe the answer is:
morse
'book detective' is the definition.
(Inspector Morse from books by Colin Dexter)
'bite for the most part' is the wordplay.
'bite' becomes 'morsel' (synonyms).
'for the most part' means to remove the last letter.
'morsel' with its final letter taken away is 'MORSE'.
'showing' acts as a link.
(Other definitions for morse that I've seen before include "Radio code inventor" , "Code using dots and dashes" , "Code inventor, Samuel" , "Dot-dash code inventor" , "Fictional inspector; code" .)