English reader, a Liberal, relating to voters (9)
I believe the answer is:
electoral
'relating to voters' is the definition.
(I've seen this before)
'english reader a liberal' is the wordplay.
'english' becomes 'E' (abbreviation).
'reader' becomes 'lector' (synonyms).
'a liberal' becomes 'al' (I've seen this in other clues).
'e'+'lector'+'al'='ELECTORAL'
(Other definitions for electoral that I've seen before include "Relating to voters" , "List of voters" , "Relating to polls" , "concerned with votes" , "- roll details all eligible to vote" .)