"A Study in Scarlet" detective (6)
I believe the answer is:
holmes
'a study in scarlet detective' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for holmes that I've seen before include "Champion solver" , "Conan Doyle's creation" , "Conan Doyle's 18" , "Conan Doyle creation" , "Famous detective" .)