Region possibly showing neglect (6)
I believe the answer is:
ignore
'neglect' is the definition.
(synonyms)
'region possibly' is the wordplay.
'possibly' indicates an anagram.
'region' anagrammed gives 'IGNORE'.
'showing' is the link.
(Other definitions for ignore that I've seen before include "Region in which to snub" , "Cut head off" , "Intentionally disregard" , "Slight" , "Give no attention to" .)