Even so, nerve affected article to a smaller extent (12)
I believe the answer is:
nevertheless
'even so' is the definition.
(synonyms)
'nerve affected article to a smaller extent' is the wordplay.
'affected' indicates an anagram.
'article' becomes 'the' (the definite article in English).
'to a smaller extent' becomes 'less' (I've seen this in other clues).
'nerve' with letters rearranged gives 'never'.
'never'+'the'+'less'='NEVERTHELESS'
(Other definitions for nevertheless that I've seen before include "But always" , "at any rate" , "anyhow" , "However" , "Notwithstanding" .)