Enjoying fewer rights, poor endured pig liver (15)
I believe the answer is:
underprivileged
'enjoying fewer rights' is the definition.
(with fewer privileges or rights)
'poor endured pig liver' is the wordplay.
'poor' is an anagram indicator.
'endured'+'pig'+'liver'='enduredpigliver'
'enduredpigliver' with letters rearranged gives 'UNDERPRIVILEGED'.
(Other definitions for underprivileged that I've seen before include "In need" , "Poor" , "no advantages" .)