Fictional detective’s name at end of passage (6)
I believe the answer is:
alleyn
'fictional detective's name at end of passage' is the definition.
I can't judge whether this definition defines the answer.
'name at end of passage' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'at end of' is a charade indicator (letters next to each other) (some letters go at the end of others).
'passage' becomes 'alley' (I've seen this before).
'n' after 'alley' is 'ALLEYN'.
Can you help me to learn more?
(Other definitions for alleyn that I've seen before include "Ngaio Marsh's detective" , "Ngaio Marsh's inspector" , "Ngaio Marsh detective - founder of South London school" .)