Subject of article by this writer (5)
I believe the answer is:
theme
'subject' is the definition.
('theme' can be a synonym of 'subject')
'article by this writer' is the wordplay.
'article' becomes 'the' (the 'definite article' part of speech).
'by' is a charade indicator (letters next to each other).
'this writer' becomes 'me' (the person who is writing these clues).
'the'+'me'='THEME'
'of' acts as a link.
(Other definitions for theme that I've seen before include "Topic for discussion" , "Subject matter, motif" , "basis for variations" , "Subject (on which person writes, speaks)" , "Musical idea; topic" .)