Taken from Poirot, it lends book name (5)
I believe the answer is:
title
'book name' is the definition.
(I've seen this in another clue)
'taken from poirot it lends' is the wordplay.
'taken from' says the answer is hidden in the clue.
'TITLE' is hidden within 'poirot it lends'.
(Other definitions for title that I've seen before include "Right - name - rank" , "Name, honorific" , "Handle" , "Designation of honour, rank or office" , "Distinctive name" .)