Author Gaiman (4)
I believe the answer is:
neil
'author gaiman' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for neil that I've seen before include "Boy's name" , "-- Sedaka, US singer" , "-- Armstrong, Apollo astronaut" , "One of 14 DIAMONDS] 's" , "1969 moon walker" .)