Articles by the writer writing to overturn conviction (7)
I believe the answer is:
atheism
'conviction' is the definition.
(atheism is a belief or conviction)
'articles by the writer writing to overturn' is the wordplay.
'articles' becomes 'athe' ('a' and 'the', indefinite and definite articles).
'by' is a charade indicator (letters next to each other).
'the writer' becomes 'I' (the person who is writing these clues).
'writing' becomes 'MS' (abbreviation for manuscript).
'to overturn' shows that the letters should be reversed in order.
'ms' back-to-front is 'sm'.
'athe'+'i'+'sm'='ATHEISM'
(Other definitions for atheism that I've seen before include "Non-belief in God" , "Disbelief in a god" , "Disbelief in gods" , "A lack of faith" , "Lack of belief in the existence of God" .)