Neglect of ruined region (6)
I believe the answer is:
ignore
'neglect' is the definition.
('ignore' can be a synonym of 'neglect')
'ruined region' is the wordplay.
'ruined' indicates an anagram.
'region' anagrammed gives 'IGNORE'.
'of' is the link.
(Other definitions for ignore that I've seen before include "Pass over" , "bypass" , "Discount" , "Dismiss" , "Forget" .)