Both needy characters livid at being excluded by society (6,3,4)
I believe the answer is:
beyond the pale
'being excluded by society' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'both needy characters livid' is the wordplay.
'characters' indicates an anagram.
'livid' becomes 'pale' (synonyms).
'both'+'needy'='bothneedy'
'bothneedy' is an anagram of 'beyondthe'.
'beyondthe'+'pale'='BEYOND THE PALE'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for beyond the pale that I've seen before include "Socially unacceptable" , "Morally or socially intolerable" , "Not understood by untanned people" , "Unthinkable" , "Unacceptable (behaviour)" .)