Writer, slim, involved with count (9)
I believe the answer is:
columnist
'writer' is the definition.
(I know that columnist is a type of journalist)
'slim involved with count' is the wordplay.
'involved with' is an anagram indicator (involved can mean confusing or complex).
'slim' with its letters mixed up with 'count' makes 'COLUMNIST'.
(Other definitions for columnist that I've seen before include "writer" , "leader?" , "Journalist making regular contributions" , "Waters or O'Toole, say" , "Contributor to newspaper" .)